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After exposure of nymphs of some Pyrrhocorid bugs to contact with certain papers or wood chips, abnormal adults are produced. Some have crumpled wings (distorted adults) and a proportion of these do not berrd, others have wing buds resembling those of a last-stage nymph and can never breed (juvenile adults). A study was made on Pyrrhocoris apterus L. and Dysdercus intermedius Dist. of the source of the factors causing these abnormalities, which were more severe in the latter species.Exposure of nymphs to paper fro the Scientific American or the Sunday Express resulted in the production of 60–100 per cent. ‘juvenile’ adults, the others showing lesser deformities. Chips from the Baisam Fir (Abies balsamea) resulted in almost 100 per cent. ‘juvenile adults’ in Dysdercus and over 80 per cent. distorted adults in yPyrrhocoris. Chips from two other common American pulp trees (Pseudotsuga taxifolia and Tsuga albertiana) resulted in only a few distorted adults and no ‘juvenile adults’. Several chemial pulps were tested but none caused deformities, and it was conculded that the chemical processes removed all the active priniciples, even from the wood of the Balsam Fir. Mechanically produced pulp from the Balsam Fir was, in contrast, fully active. It was conculded that daily newspapers may contain enough mechanical pulp from active woods to produce the deformities, but that the active material must be in substances added later in manufacture to the papers used in the Scientific American, some copies of Nature, and tissues.A number of tree products (mainly terpenoids) that are commonly added to paper in the final stages of manufacture were tested as extracts applied to filter paper. Tall oil rosin had little or on effect on the growth of either species, but it resulted in an increase in the number of eggs laid. Gum rosin had little effect on either species, except to produce a few distorted adults. Wood rosin likewise had little effect on P. apterus, but produced many distorted adults of D. intermedius, of which very few laid eggs. Bornly acetate, a common component of the tree orsins, produced some distorted adults of both species, and greatly reduced fertility in D. intermedius.None of the qctive mqteriqls affected locusts (Schistocera gregaria Forsk. and Locusta migratoria migratorioides R. & F.) except that myrrh oil (a terpenoid) increased the rate of sexusl maturation.

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The basic recurrence equations given in our previous paper have to be modified when males and females are differentiated. The modifications we gave are incorrect because we ignored the deviations from Hardy–Weinberg equilibrium when sampling and selection are applied separately to the two sexes. Appropriate corrections are presented in this paper.

SEVERAL years ago, Gibbs,1 summarizing contributions of biochemistry to plant taxonomy, recognized the importance of the then relatively new techniques of paper chromatography and forecast their wide application, to systematics. Although a number of workers have applied chromatographic techniques to taxonomic problems in both botany and zoology2, the use of these techniques is not nearly commensurate with their potential value, perhaps because the cooperation of taxonomists and persons trained in biochemical analysis has been slow to develop. The present communication constitutes a brief description of work currently under way which is to be reported in greater detail elsewhere;3 the chomatographic analysis of individuals from a natural hybrid swarm of Baptisia laevicaulis × B. viridis (family Leguminosae), and correlation of these data with a similar analysis of the parental species collected in pure populations. Three other species of Baptisia were also examined chromatographically. Since this genus contains about 30 species of wide occurrence in the eastern United States, and hybridization among these species is common, it is highly probable that the scope of the present investigation will be extended. In this study we were particularly concerned with the recombination of biochemical components peculiar to each parental species among the hybrid and back-crossed individuals.

In their recent paper, Waddington & Robertson (1966) discuss the general importance of disruptive selection and make various points that call for comment.First, their statement that ‘It is most desirable that Thoday's results … should be repeated, with special attention to the strict virginity of the flies used, …’ appears to some readers as a scarcely veiled imputation that my experiments, especially that of Thoday & Gibson (1962), were executed without technical competence, though Waddington has informed me such imputation was not intended.

IT SEEMS to me that the method of approach suggested by Dr. Martin is the only one available at the present time. It has been demonstrated that, under certain conditions, resistance to lymphomatosis can be increased by means of selection. From a purely practical point of view, it should be pointed out that the ultimate success of Dr. Martin’s program depends on the assumption that strains of birds selected for resistance to lymphomatosis under the conditions of one flock would also be resistant under entirely different conditions. This assumption needs testing before any extended program of selection is undertaken. There is some evidence that resistant strains from one flock were not resistant when placed in another. The development of useful strains under such conditions would be very difficult. There is another point that should be tested. It is possible that there may be several types of agents or circumstances capable . . .

It is hardly possible to give in a short paper a convincing account of a theory which must be based on an extensive array of facts, only a part of which (i) have thus far been presented. The problem has lately been much discussed from the ontogenetic point of view (see the exhaustive bibliography in Foster, 7). The morphological and phylogenetic standpoints, however, have been very much neglected. The ontogenetic investigations partly support my theory but more often contradict it. This, however, is of no consequence, as a morphological problem must be solved primarily by comparative morphological investigations as well as by the evolutionary history of plant organs. Even Gliick (9, p. 637-638), a prominent member of Goebel's school, correctly pointed out that ontogenetic facts do not always agree with the true morphological character of the organ. Thus he mentions that the stamens of some plants (Euphorbia, Casuarina, Najas, Typha, Cyclanthera) though they clearly belong ontogenetically to the axis, are undoubtedly metamorphosed phyllomes. Many other cases (see Velenovsky, i i) of a similar nature have been emphasized, and Schr6dinger (io, p. I85-I86) points out that in not less than five genera of the Cunoniaceae the stipules arise " nachweislich echt freiachsenbuirtig, d.h. aus selbstandigen Primordien, fur deren Vorw6lbung im Innern des Sprossgipfels vollkommen selbstandige Zellvermehrungsherde differenziert werden." Hardly any botanist, however, would assume that they do not belong to the respective leaves but that they are organa sui generis. It is hardly necessary to repeat in detail my theory of the phylogenetic differentiation of the phyllome according to which the most primitive form is a one-membered, broadly inserted leaf which in further evolution differentiated into a lower member (the sheath) as the predominantly mechanical organ and the blade as an organ designed for assimilation. In further evolution the auricles of the sheath, which are of rather common occurrence, lengthen while the sheathing part shortens (stipulae adnatae, called by Gluck more appropriately stipulae vaginales); finally, after total disappearance of [The Journal for March (I8: 147-235) was issued March 23, I93I.]

PAPER electrophoresis has stimulated the investigation of proteins in inp vertebrate biological systems that were formerly considered too minute for analysis. The preliminary phases of these investigations are exploratory, and the emphasis has thus far been placed upon the number of fractions detectable and their mobility within a given system. Reports of from two to six protein blood fractions have been made for vari

I F selection operates independently on each locus, its action on the large amounts of genic variability discovered in many populations (e.g., LEWONTIN and HUBBY 1966) would cause excessive genetic loads compared with the actual situation. In order to accommodate selection for many genes, threshold or truncationselection models have been proposed assuming heterozygote superiority ( SVED, REED and BODMER 1967; KING 1967; MILKMAN 1967; WILLS, CRENSHAW and VITALE 1970). As a typical form, MILKMAN and WILLS et al. assumed that the individuals having the largest number of heterozygous loci are selected to produce the next generation. Selection acts at the phenotypic level, the phenotype being the result of genotypic and environmental (including chance) effects. Thus. for any trait including fitness. large phenotypic values do not always follow from large genotypic values. We have attempted to examine the genetic consequences of the typical phenotypic truncation selection on the basis of the genetic parameters for viability obtained in D. melanogaster. If this truncation-selection occurs, it is probably operating mainly in the period from egg to adult. We have estimated the genotypic and environmental variances, and the heritability (broad sense) of egg-adult viability. Two experiments were conducted, one to estimate the variability in relative viability and the other to estimate mean viability. Employed were second chromosomes from 691 extracted by the marked inversion technique from a population in a state park near Raleigh, North Carolina. This population is probably near equilibrium (MUKAI et al. 1971 ) . To estimate variability, the relative viabilities of 688 random heterozygotes were estimated using the Cy method (cf. WALLACE 1956). Crosses were made between five Cy/+i females and five CY/+^+^ males (between successively numbered lines where the subscript indicates line number), and Cy is SMI ( C y ) . Four days after the crosses were made, all flies were transferred to the second vial for another four days and then discarded. The numbers of C y and of wild-type flies of each pair of vials were pooled, and the relative viability of heterozygous wild

Traditionally, the teaching of biology has been characterized by abrupt discontinuities with one branch of the subject largely isolated from another; thus botany has been distinct from zoology intellectually and sometimes in geographical location as well. During recent years welcome changes have been initiated in the direction of a more interdisciplinary approach, beginning in the schools under the influence of the Nuffield Projects and spreading more slowly within the universities. In the midst of these changes in biological thought and attitudes, one of the great unifying themes has been heredity. It is a great pleasure to contribute this short paper in honour of Professor Ford, since it provides me with an opportunity to pay tribute to him on behalf of the many students of biology both at Oxford and elsewhere, who have been stimulated and inspired by his teaching of genetics, particularly that aspect of the subject which has become so peculiarly his own—ecological genetics.

The division ofCuscuta s.l. into 4 genera, based mainly on floral morphology, is corroborated by their embryology. Several new combinations inMonogynella andGrammica are proposed.

The practical application of electrophoretic analyses of proteins of mammalian sera and hemoglobins by simple methods is described. Twenty-five taxonomic relationships, most of which have been controversial, are reviewed, and decisions based on blood proteins and hemoglobins are given. In 19 instances clarifications of relationships were obtained, but in 6 instances the proteins did not help. In the past two decades much information regarding proteins has accumulated. The complex techniques developed in biochemical laboratories are now being evaluated in systematic biology laboratories (Dessauer, 1966a, 1966b; Gibbs, 1965; Manwell and Kerst, 1966; Nadler and Hughes, 1966). Abundant evidence indicates that protein characteristics are conservative, genetically controlled, and may be helpful in taxonomic studies. Also it has been demonstrated that polymorphic occurrence of certain protein molecules gives information at subspecies and population levels (Naevdal, 1965; Kirsch, John A. W., personal correspondence). This paper primarily summarizes our experience of correlating protein characteristics with other taxonomic data and, secondarily, assesses the future possibilities in this field. Since 1957 we have electrophoretically examined blood specimens from large numbers of mammals (Johnson, Wicks, and Brenneman, 1959; johnson and Wicks, 1964). Representatives of all orders of the Mammalia have been examined, and a survey of this class is now possible. Our preliminary work was done with paper electrophoresis which is well suited for basic survey because it is easily used and the results are readily interpreted. Applications of more refined procedures in recent years indicate that both advantages and drawbacks may be expected using these more complex procedures.

The use of the Jolicoeur-Brunel hexagonal diagrams to demonstrate selection in biological populations was tested in a computer-simulation study.—The results show convincingly that the probabilities associated with the six deviation patterns illustrated in the hexagonal diagrams are not equal, but depend on the sample size and in particular on the genetic composition of the sampled population. The diagrams thus cannot be used to demonstrate selection, but only to illustrate trends of deviation patterns, which may be real biologically.

Theoretical calculations and population cage data are presented to illustrate the use of compound chromosomes to change the genetic structure of insect populations.

Evidence of strong association of alleles at the Esterase-5 and adult Acid phosphatase-6 loci with the Sex Ratio and the Standard X chromosome arrangements in D. pseudoobscura is presented. There is no differentiation at these two loci, either in the Sex Ratio or the Standard arrangement from two widely separated geographic populations. At the Esterase-5 locus, alleles characteristic of one arrangement are found in low frequencies in the other arrangement. It is concluded, from these and other observations that the differentiation between the Sex Ratio and the Standard arrangement, at these two loci, is a result of natural selection favoring different coadapted gene blocks in these arrangements. The average heterozygosity at these two loci in different karyotypes is in the following order: ST/SR > ST/ST >> SR/SR which agrees very well with the fitness estimates of these karyotypes.

The value of electrophoretic techniques for supplementing classical systematic methods was recently demonstrated (Dessauer, 1966). These techniques were applied at all taxonomic levels and, for lizards specifically, the analysis of protein patterns was at least as sensitive as morphological comparisons at the intraspecific, specific and generic levels (Dessauer, Fox and Pough, 1962; Gorman and Dessauer, 1965, 1966; Maldonado and Ortiz, 1966; Guttman, 1970a, 1970b). Hemoglobins, being charged molecules, migrate in an electric field. The rate of migration depends, in part, upon the shape and size of the protein and its electric charge; therefore, the electrophoretic mobility is an important characteristic of the molecule. Foreman (1960) suggested that differences in the electrophoretic properties of hemoglobins be used to establish levels of taxonomic relationship. However, inconsistent results were obtained when hemoglobin patterns were used for species recognition. Manwell and Baker (1963) described a new species of sea cucumber based on hemoglobin and enzyme differences; the hemoglobins of similar species of sunfish were different (Manwell and Childers, 1963); hemoglobin patterns distinguish many species in the roquet species group of Anolis (Gorman and Dessauer, 1966); certain members of the torquatus species group of Sceloporus possess hemoglobins which migrate at the same rate (Guttman, 1970a); the genera of sand lizards are characterized by an electrophoretically identical hemoglobin component (Guttman, 1970b). On the other hand, intraspecific variation of hemoglobin components was noted in lizards (Guttman, 1970a), anurans (Gillespie and Crenshaw, 1966; Guttman, 1967, 1969, 1971; Brown and Guttman, 1970), and urodeles (Guttman, 1965; Newcomer, 1967). Although Dessauer, Fox and Ramirez (1957) examined the hemoglobin components of many genera of lizards, the technique they employed, paper electrophoresis, didn't permit the resolution possible with the more sophisticated methods presently available. The present survey of the hemoglobin components of selected Old and New World lizards was initiated to determine whether characteristic specific, generic or familial patterns exist.

VERTEBRATE neurohypophysial hormones have a common structural pattern characterized by a chain of nine amino-acid residues with a disulphide bridge connecting the amino-acids in positions 1 and 6. There are usually two hormones in each species, the active principles rarely varying from one species to another within a given class. Thus oxytocin and arginine vasopressin have been chemically identified in five species of mammals belonging to the orders Primates, Artiodactyla, Perissodactyla and Cetacea. Isotocin (Ser4-Ile8-oxytocin) and vasotocin (Arg8-oxytocin) have up to now been isolated from six species of bony fish belonging to the families Gadidae, Scombridae and Cyprinidae. The structural variations which occur between one vertebrate class and another are confined to one or two amino-acid substitutions in positions 3, 4 or 8 (for a review of this subject see ref. 1).