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Summary The fine morphology of the buccal capsule and intestine (midgut) of the marine free-living nematode Odontophora deconincki was investigated. The cheilostome is armed with six equal claw-like odontia that can evert radially by opening the mouth. Light-refracting accessory buccal structures within the cheilostomatal cuticle alternate with odontia and consist of two elements: anterior armilloids and posterior granular armilliths. The buccal cavity (pharyngostome) is surrounded by a complex of longitudinal and oblique muscles partially attached to the cheilostome cuticle at the sites of the accessory buccal structures and enabling a wide opening of the mouth. With the described stoma condition, the nematode probably scrapes food particles from the substrate surface. In cross-section, the midgut consists of 5-7 cells that appear uniform throughout its length. An extracellular matrix (glycocalyx) over the microvillar brush varies in thickness and stratification depending on presence or absence of food content in the lumen. Abundant spherocrystals (globular inclusions with concentric striations) were present in all gut cells. No indication of endocytosis or digestive vacuoles was observed in the gut cells and extracellular digestion predominates. Most specimens had a gut content formed from a long cylinder of compressed flocculent material with some barely identifiable components and few spherocrystals expelled from the enterocytes. We assume that the nematode diet comprises a wide range of objects, mainly eukariotic epigrowth organisms, which are shorn off and scraped from the surface of sand grains and then ingested.

Two new plectid species from India are described and illustrated. Plectus glandulatus sp. n. has 917-1307μm long body; strongly annulated cuticle; conspicuously large hypodermal glands; ovoid amphidial apertures; offset lip region; separate, globular, lips; thickly cuticularised, arcuate, cheilostomal walls; basal bulb with four to five paired denticulate ridges; a pair of pseudocoelomocytes located posterior to the cardia and tail with a subterminal spur and three pairs of caudal setae. Chiloplectus indicus sp. n. has 695-1041μm long body; thick, transversely annulated, cuticle; three lateral incisures; markedly offset, narrow, lip region; lips with conical apices and slightly raised papillae; inner margin of lips forming well cuticularised oral framework; prorhabdion as long as wide and comprising 20% of the stoma length; basal bulb with six pairs of denticulate ridges; paired pseudocoelomocytes located posterior to the cardia, genital tract weakly developed and tail with one median spur and two pairs of caudal setae.

A new genus and species, Aphanonchus inlermedius, is described from Lake Tahoe, California. It is characterized by a finely annulated cuticle with narrow lateral field, soft cephalic setae, unispiral to irregularly circular amphids which occupy about 1/2 of the corresponding head width, stoma consisting of a narrow anterior and a wide, sclerotized posterior part. Lateral epidermal glands and pores prominent. Ventral gland lobed and associated with coelomocytes, excretory duct cuticularized opening anterior to mouth opening. Female reproductive system amphidelph, vagina with prominent sclerotization. Male with a series of tuboid supplements and a medioventral row of numerous alveoli extending to the anterior end. The new genus is intermediate between Paraphanolaimus and Anonchus. Paraphanolaimus mullipapillatus (Daday, 1905) is transferred to the new genus. The morphology of the head end and of the vaginal musculature is described in detail.

Three new species of Paraphanolaimus Micoletzky, 1922 are described, one from southern Chile, P. terrestris sp. n., is characterized by length of female, number of smooth, coarse annuli, conoid tail with tubular posterior portion, long neck region (b = < 4.5). P. latescens sp. n. from Lizard Island, Great Barrier Reef, Australia is distinguished by length of females and males, shape of tail, size of spicules and number of lateral epidermal glands (LEG). P. tahoensis sp. n. from Lake Tahoe, California, is distinguished by length of females and males, number of annuli, number and size of pairs of prominent LEGs, large oval amphids, rounded lips of vulva, perpendicular vagina, number of supplements, and size and shape of spicules and gubernaculum. Specimens of P. anisitsi Daday, 1905 from southern Chile and from the Mendocino coast of California provide further information on that species. P. micoletzkyi Khera & Chaturvedi, 1977, was described from a single female and distinguished by a set-off posterior bulb in the pharynx immediately behind the nerve ring. This character makes doubtful its placement in the genus Paraphanolaimus and the species is assigned to species inquirendae.