564 John Beard 



topoda and Trematoda , but placed it among- the Chaetopoda. By Van 

 DER HoEVEN it was classed among the parasitic Crustacea, while Die- 

 sino classed it with Hìsfriobdella among the Leeches. It has been 

 placed among the TurbeUaria by M. Schultze, among the Crustacea 

 by Leydig and Carus , while Semper considered it impossible without 

 knowledge of its development to determiue its position with any pre- 

 tensiou to certainty. Nevertheless bis figure of a larva with two pairs 

 of legs , and some external resemblance to a NaupKus led Carus and 

 others to the conclnsion, that the group had some relationship with the 

 Crustacea — a view held so recently as ISSI by Prof. Hensen in Her- 

 mann's Handbnch der Physiologie. Bd. VI. p. 99 , who speaks of it as 

 a small )iKrebschen((. Four Zoologists bave in their works recognised its 

 trae nature. R. Leuckart, Metschnikoff , Claus and Bütschli ali 

 agree in plaeing it among the Chaetopoda — a position which its de- 

 velopmental history most eertainly entitles it to. Graff in bis Mono- 

 graph of the Genus places it near the Tardigrada and unites the Tardi- 

 grada^ Linguatididae^ ^ìid Mgzostomidae in one di vision sìB /Stec/ielopoda. 



This view is repeated as the result of bis latest researches on the 

 Challenger- and other Myzostomidae in the Tageblatt der Versammlung 

 der deutschen Naturforscher und Ärzte in Freiburg 1S83, report oi 

 First Meeting. 



It would be useless to enter into a long discussion of the reasons 

 for refusing to place Myzostotna among the Trematoda^ Leeches, Tur- 

 hellaria or Crustacea. They are obvious on the face of it , for the de- 

 velopment as described in the precediug pages and figured in the Plates 

 cannot be made to fit in with the development of any of these groups. 

 And thus there only remain to discuss the claims of the Tardigrada and 

 Chaetopoda. ßeasons must be given against their relationship to the 

 Tardigrada , because they bave been placed near these by the greatest 

 authority on the genus, Prof. Graff. So far as I know the only paper 

 we possess on the development of the Tardigrada is one published in 

 1851 by Kaufmann'. The development is there described and figured 

 as being a direct one, and in no way does any part of the segmentation 

 and complicated development of Myzostoma allow of comparison with 

 that of Macrobiotus. Nor are the superficial resemblauces in adult aua- 

 tomy such as really to justify an assumptiou of relationship. Some 

 species of Myzostomidae like the Tardigrada are hermaphrodite , but 



1 Zeitschr. f. wiss. Zool. Bd. III. — A remarkably good paper considering 

 that it was written long before our modern methods of research were invented. 



