Dorylaimus conicaudatus, Ditlevsen, 1927

Ditlevsen, Hjalmar, 1927, XXII. Free-living Nematodes from Greenland, Land and Freshwater., Meddelelser om Gronland 22, pp. 174-198 : 179-180

Dorylaimus conicaudatus n. sp.

Locality: Kapisigdlit. The Fjord of Godthaab . 9. 7. - 24. 8. 1926. Reisinger and Steinböck.

Female: Length 2,0 mm. α =30; ß = 6,1; y = 30.

Vulva 41,7 %.

This very nice form is present in several specimens, some of which are fullgrown females, while the rest comprises young individuals. No male was seen.

This species is beyond doubt nearly related to the subgenus Doryllium . It has a straight, rather long and relatively slender spear, and this is continued by a pseudo-spear much like that known in STEıNr-:ıüs D. macrodoraides , but it is easily distinguished from this form, by means of the relatively short oesophagus and the shape of the tail.

The front end narrows quickly, and in this respect it is very much like D. groenlandicus . The head is rounded and neither lips nor papillae are obvioufl ( fig. 15 ).

The foremost half of the oesophagus is thin, and at the end of this the nerve ring is found; it is hardly observable, and behind it the oesophagus increases towards its base. Immediately caudad to the nerve ring a pear-shaped, rather lengthened, body is observed ( fig. 18 ). It is situated at the ventral side of the oesophagus and is much like the ventral gland, known in most of the marine species of freeliving Nematodes. It was observed in nearly all the specimens at hand, but unfortunately I was not able to observe where it opens; I am most inclined to mean that it must be into the oesophagus itself and not at the surface of the body. The ante-rectum is relatively long and makes almost the half of the length of the oesophagus.

As to the shape of the tail, I shall remark that in most of the specimens it is conical with rounded tip as shows the fig. 16; but in some few it is somewhat more acute as in fig. 17 , only the tip is never pointed. The female pore is situated somewhat cephalad to the middle of the body. The ovaries are rather short and symmetrical. Though several full-grown females are present, not a single was seen with shell-eggs in the uterus.

Figures

Fig. 15. Dorylaimus conicaudatus. Front end.

Fig.

Fig. 18. Dorylaimus conicaudatus Qesophaggal gland.

Fig. 17. Dorylaimus conicauda tus. Hind part of a specimen with more acute tail