38 HISTORY OP THE SUBJECT. 



sub-order [Nemertinea Jnopla), though his description of the family requires some additions, and 

 the application of the test of the " lobe-shaped snout " is of no moment. The genus Linens is 

 good, but Cerebratulus, the next or eighth genus, requires further examination. The ninth genus, 

 Nemertes, seems quite superfluous, for the Notospermus drepanensis of Huschke will fall under 

 other genera. It appears to be an example of the Anopla. The tenth genus, Ophiocephalus, is 

 also very much open to doubt, since the Ophyocephalus murenoides of Delle Chiaje may be a 

 variety of Linens marinus. His third family [Gymnocephalidce) is certainly worthy of separation, 

 and the sole genus, Cephalothrix , is satisfactory. 



The second part of his memoir is occupied with a description of several species. Amongst 

 these, his Borlasia splendida, n.s., is the Cerebratulus spectabilis of De Quatrefages ; Nemertes 

 octoculata, n.s., had often been described before ; while Cephalothrix ocellata, n.s., and C. longis- 

 sima, n.s., may conveniently, as well as correctly, be included under the well-known form 

 Cephalothrix linearis. 



The third division is devoted to the anatomy of the group. He did not recognise the 

 differences existing in the muscular system of the body-wall of the various types ; the position of 

 the mouth in the Enopla was misunderstood ; and he had no correct knowledge of the true 

 relations of the muscular sheath of the proboscis, or of the minute anatomy of the wall of the 

 latter. He did not discriminate with sufficient accuracy the cephalic sacs and the posterior ending 

 of the ganglia in Linens. While the author went astray in these and several other anatomical 

 points, he made advances of considerable interest in others, so that his paper is a valuable and 

 most praiseworthy contribution on the Nemerteans. Keferstein's classification, with all its imperfec- 

 tions (and a few superadded), has been adopted by J. V. Carus in his ' Handbuch der Zoologie/ 



Diesing now issued a third brochure on the subject, 1 bringing the literature up to the 

 time; but he did not alter his arrangement, except when introducing "new" genera, many of 

 which, however, had previously appeared in his publications. On the whole, the labours of the 

 writer have chiefly been of value in rendering us acquainted with the various papers relating to 

 the Nemerteans ; and it will be the safest course for the investigator simply to regard these 

 works in this light, and to remember that the author had the disadvantage of being unacquainted 

 with the living animals, and strove to be of use to science even when attacked by a great misfortune. 



E. Claparede, in a memoir 2 published shortly after Keferstein's, makes some further remarks 

 on Prosorhochmus Claparedii. He mentions that he had seen ova in the body of the adult 

 worm, and doubts the correctness of Professor Keferstein's statement, that he had found three 

 stylet-sacs in a young specimen, since there are only two in this and other Nemerteans. He 

 also describes a new species of Tetrastemma, viz., T. marmoratum, which, however, is only the 

 T. dorsalis of Abildgaard ; and, lastly, he adds a note on (Erstedia pallida. His observations 

 were made on the coast of Normandy. 



In the following year, Dr. Cobbold 3 did not hesitate to place the Turbellaria amongst the 

 Sterelmintha ; yet I am unable to find out any sound reasons in his description for this grouping, 

 to which I am inclined to object. He arranges them as the first order, Turbellaria, under the 



1 ' Nachtrage zur Revision der Turbellarien.' Sitzungsb. d. Kais. Akad. d. wissensch. Wien, 1863 

 (46 Bd.), p. 5. 



2 ' Beobachtungen liber Anat. u. Entwicklung. wirb. Thiere/ &c, pp. 23 and 24, taf. v, f. 10—14. 

 Leipzig, 1863. 



3 ' Entozoa : An Introduction to the Study of Helminthology/ &c., chap. i. London, 1864. 



