418 Di\ W. Michaelsen on the Enchytrasidge. 



claim generic rank. They have S-shaped seta3 and are desti- 

 tute of the salivary glands. As the first thing, therefore, I 

 show that the genus Pachydrilus, Clap., must be maintained. 



Not to be unjust towards Eisen, I must state that the 

 incompleteness of Olapar^de's generic diagnoses and the incon- 

 sistencies of which that author was guilty in the arrangement 

 of his species in the respective genera could not but cause the 

 soundness of the latter to appear doubtful, especially to a 

 naturalist who had only preserved materials to work upon, 

 and could not by his own investigations learn the coincidence 

 of the principal character indicated by Clapar^de, the colour 

 of the blood, with other essential peculiarities. The reproach 

 of inconsistency relates to the position of Claparfede's Pachy- 

 drilus ZacfeMi-, which, indeed, plays an important part in Eisen's 

 statement. This Enchytrajan does not belong at all to the 

 genus PachydriluSy as appears from Claparfede's own state- 

 ments. It possesses colourless blood and " Les aiguilles sont 

 parfaitement rectilignes, a I'exception de I'extr^mite interne, 

 qui est recourbee de manibre a former un petit crochet" (1, 

 p. 17). With Pachydrilus proximus^ Czern.*, Enchytrceus 

 Mdhii, aut-t, and E. spicidus, Leuck.f, it forms a group of 

 Enchytrcei which could be arranged with the Pachydrili only 

 on account of their marine habitat. The circumstance that 

 they possess no dorsal pores is not of consequence, for many 

 other species of Enchytrmus want these without their position 

 being thereby rendered doubtful. 



The question now arises whether Eisen's system is to be 

 completely rejected, or whether it may not be combined vvith 



* (3) Czerniavsky/'Materialia a. zoograph. pontic, comparat.: Fasc.iii. 

 Vermes," in Bull. Soc. Imp. Nat. Mosc. 1880, no. 2. 



t (4) Michaelsen, ' Ueber Enchytrceus Mohii und and. EncJiytrceen^ 

 Kiel, 1886. 



X (5) Frey und Leuckart, ' Beitrage zur Kenntoiss der wirbellosen 

 Thiere.' (Some time since my father sent me from Ouxhaveu three 

 living specimens of a whitish Enchytr^id, about 10 millim. in length, 

 which is undoubtedly identical with E. splculus, Leuck. They possess 

 delicate straight setae, only a little bent at the inner extremity, 

 standing in tufts of 4-6 (on the anterior segments often even 7-8) to- 

 gether. The cerebrum is posteriorly deeply emarginate, with the lateral 

 margins converging in front, and it is rather longer than broad. The 

 seminal funnels are broad, barrel-shaped, with the margins everted. 

 A mature ovum exceeds the others considerably in size and occupies 

 nearly the whole of the body-cavity in the twelfth segment. These 

 worms, therefore, probably lay only one e^g in each cocoon, unlike the 

 other marine Enchytr^idee with which I am acquainted (see 4, pp. 8- 

 9). The seminal pouches consist of a simple, thin-walled, pyriform 

 principal part and a rather short, simple, straight, elFerent duct. The 

 worms were found below Cuxhaven outside the dyke, upon the ground 

 overflowed by the sea at flood-tide.) 



