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Quantitative analysis of samples of the stomach contents of 95 north Queensland dugongs, Dugong dugon, (63 from the Townsville area, 30 from the Mornington Island area and 2 from the Torres Strait area) and one dugong from south Queensland indicates that the diet of most consisted almost entirely of seagrasses of all available genera. Halodule was found in 95% of stomachs, followed by Halophila (89%). Cymodocea (61%) and Thalassia (39%). Seagrass rhizomes were present in all stomachs examined including that of a newborn calf. The generic composition of the stomach contents probably reflects that of the seagrass beds in the areas where the dugongs were captured and is not necessarily indicative of discrimination in selecting food. Non-epiphytic algae occurred in 51% of the stomachs, usually in small amounts. When seagrasses were abundant, dugongs appeared to eat algae often but only in very small amounts (

Sphaerocarpos texanus Austin has been found in Australia. It is probable that it is a recent introduction rather than an indigenous species. A review of the representation of the order Sphaerocarpales in Australia is presented. The order Sphaerocarpales consists of two suborders, the Riellinae and the Sphaero- carpinae. Representation of the Riellinae in Australia was reported in 1951 by Banwell when he described Riella halophila Banw. from Point Lonsdale and Dimboola, Victoria. This was reinforced in 1954 when Taylor described R. spiculata Tayl. from Portland, Victoria. For years collectors have tried to find Sphaerocarpos of the Sphaerocarpinae in Aus- tralia. Searches have proved fruitless and it has been recorded on more than one occasion (e.g. Carr 1956) that Sphaerocarpos does not occur in Australia. A collection in the British Museum (BM) labelled: "No. 4. Swan River. Js. Drummond.

Glycollate : dichlorophenolindophenol reductase, or glycollate dehydrogenase, was present in 15 green marine algae and one blue-green alga collected around Lizard Island, Australia. No enzyme activity was found in red or brown algae or zooxanthellae. Glycollate dehydrogenase was also found in the marine grasses Cymodocea and Thalassia, and this is the first report of it in higher plants. However, glycollate oxidase was present in the particulate fraction from Halophila, another marine monocotyldonous plant. On Lizard Island, the C3 plants, the C4 salt plants Distichlis and Salsola, and a crassulacean acid metabolism plant, Sesuvium all contained glycollate oxidase.

Systematic and ecological implications were shown for Australian seagrasses by studies of isozymes, secondary compounds and experimental cultures. In Halophila, small- and large-leaved plants which occur sympatrically from northern Queensland to New South Wales and were referred to H. ovalis (R.Br.) Hook. f. differed in isozymes and secondary compounds and maintained leaf size differences in experimental cultures. The small-leaved plants should be referred to a different species. In Halodule, narrow-leaved plants that were referred to H. uninervis (Forsk.) Aschers. and H.pinifolia (Miki) Den Hartog were examined. In experimental cultures, narrow-leaved plants from Thursday Island produced both tridentate and rounded serrulate leaf tips and differed in isozymes and secondary compounds from wide-leaved plants. The narrow- leaved plants should be referred to H. pinifolia and the wide-leaved plants to H. uninervis. In Zostera, small- and large-leaved forms of Z. capricorni Aschers. which occur sympatrically in Queensland and New South Wales have similar isozymes that differ from those of Z. muelleri Irmisch. ex Aschers. of South Australia. Experimental cultures of Z. capricorni continued to produce 5-nerved leaves and those of Z. muelleri, 3- nerved leaves. In Amphibolis, cultures of A. antarctica (Labill.) Sonder & Aschers. and A. griffithii (J. M. Black) Den Hartog continued to show leaf differences but were similar in secondary compounds and isozymes, differing in only one of eight enzyme systems. In Posidonia, wide-leaved plants of P. australis Hook. f. continued to produce leaves in culture that differed in width from those of P. sinuosa Cambridge & Kuo but were similar in secondary compounds and isozymes, differing only in one of eight enzyme systems. The chemical evaluations and experimental cultures suggested wide differences in Halophila and in Halodule but indicated only narrow differences in the other three genera.

Eighteen species of Copepoda are reported from the metahaline seepage pool of Di Zahav on the coast of the Gulf of Elat. Ridgewayia typica, Euryte sp., Orthopsyllus linearis, Typhlamphiascus confusus, Laophonte inornata and Heterolaophonte quinquespinosa are dominant. The composition of the fauna of this high-salinity pool is discussed. A new genus and two new species of Harpacticoida are being described: Dizahavia halophila n. gen. n. sp. and Cletodes dorae n. sp. A new genus and species of Cyclopoida is described, too: Cyclopuella sinaitica n. sp. The species Ridgewayia typica (Calanoida) is redescribed in detail.

The name Ustilago hypodytes was rejected as a nomen dubium by Fischer & Hirschhorn (1945) . Evidence is here adduced to show that the application of the name is not in doubt. The name is re-instated. The relationship of U. hypodytes with the American species U. nummularia Speg., U. halophila Speg., U. spegazzinii Hirsch, and U. williamsii (Griff.) Lavrov is briefly discussed, U. nummularia and U. spegazzinii being considered synonymous.

LITTLE is known of the life history of the pigmy seahorse, Hippocampus zosterae.2 From June, 1948 to June, 1957, large samples were taken at Cedar Key, Levy Co., Florida. From February, 1950 to February, 1951, bilunar monthly collections were made at 28 stations on three grass flats during spring tide periods. Further data were obtained from seahorses collected in other parts of the Gulf of Mexico, including some from Harbor Island, Texas, which were kept alive at The University of Texas. Pushnets (Strawn, 1954a), beam trawls, and minnow seines were used to collect seahorses. Seining was discontinued when it was discovered that one person could collect more seahorses with a pushnet than two could with a seine. Three-eights-inch stretched mesh netting was used in both the pushnets and trawls because only small seahorses could go through it. Cedar Key specimens, except for a few found on vegetation floating in the channels, were taken on the grass flats bordering the islands or between these keys and the mainland. The grass flats in this area are restricted to above the extreme low water mark except for limited fringes. Deeper grass flats in clearer offshore water were not investigated. The angiosperms growing on the grass flats at Cedar Key are: Diplanthera wrightii (Ashers); widgeon grass, Ruppia maritima L.; Halophila engelmanni Ashers; turtle grass, Thalassia testudinum K6nig; and manatee grass, Syringodium filiforme Kiitz.3 Of the three most conspicuous plants, Diplanthera occurs in the shallowest water, Syringodium is predominant in the deepest water, and Thalassia is mixed in at intermediate

Background Hydrocharitaceae is a fully aquatic monocot family, consists of 18 genera with approximately 120 species. The family includes both fresh and marine aquatics and exhibits great diversity in form and habit including annual and perennial life histories; submersed, partially submersed and floating leaf habits and linear to orbicular leaf shapes. The family has a cosmopolitan distribution and is well represented in the Tertiary fossil record in Europe. At present, the historical biogeography of the family is not well understood and the generic relationships remain controversial. In this study we investigated the phylogeny and biogeography of Hydrocharitaceae by integrating fossils and DNA sequences from eight genes. We also conducted ancestral state reconstruction for three morphological characters. Results Phylogenetic analyses produced a phylogeny with most branches strongly supported by bootstrap values greater than 95 and Bayesian posterior probability values of 1.0. Stratiotes is the first diverging lineage with the remaining genera in two clades, one clade consists of Lagarosiphon, Ottelia, Blyxa, Apalanthe, Elodea and Egeria; and the other consists of Hydrocharis-Limnobium, Thalassia, Enhalus, Halophila, Najas, Hydrilla, Vallisneria, Nechamandra and Maidenia. Biogeographic analyses (DIVA, Mesquite) and divergence time estimates (BEAST) resolved the most recent common ancestor of Hydrocharitaceae as being in Asia during the Late Cretaceous and Palaeocene (54.7-72.6 Ma). Dispersals (including long-distance dispersal and migrations through Tethys seaway and land bridges) probably played major roles in the intercontinental distribution of this family. Ancestral state reconstruction suggested that in Hydrocharitaceae evolution of dioecy is bidirectional, viz., from dioecy to hermaphroditism, and from hermaphroditism to dioecy, and that the aerial-submerged leaf habit and short-linear leaf shape are the ancestral states. Conclusions Our study has shed light on the previously controversial generic phylogeny of Hydrocharitaceae. The study has resolved the historical biogeography of this family and supported dispersal as the most likely explanation for the intercontinental distribution. We have also provided valuable information for understanding the evolution of breeding system and leaf phenotype in aquatic monocots.