392 ADAM SEDGWICK. 



nary gland described by Grobben (No. 55), were part of a true 

 coelomic space. The discovery of the end-sacs in Peripatus, 

 and of their method of development, entirely confirms Lan- 

 kester's view. And it is interesting to notice that the end- 

 sac of the Crustacean green gland, as figured by Grobben, 

 resembles somewhat in the structure of its wall the end-sacs of 

 the Peripatus nephridia. 



In the Leeches the nephridia are stated by Bourne (No. 4) 

 and other observers to communicate with the vascular system. 

 I think, however, it is worth while to bear in mind the pos- 

 sibility of there having been a mistake on this point. It is 

 possible that the nephridia in the Leeches may, as in Peri- 

 patus, end in a closed vesicle which lies in, but does not 

 open, into the vascular system. Such vesicles might quite well 

 have been overlooked by the able observers who have dealt 

 with the subject, as they undoubtedly were overlooked in 

 Peripatus. 



It is interesting to notice the resemblance which would 

 exist between the transverse section of Peripatus (PI. XXIX, 

 fig. 17) and the transverse section of a Leech, if the blood 

 tracts of the former were more broken up, and the nephridia 

 of the latter did not open internally into the vascular 

 system. 



List of Papers referred to. 



1. Kennel, J. — " Entwickelungsgeschichte v. Peripatus Edwardsii u. 



torquatus," Theil ii, 'Semper's Arbeiten,' Bd. vii. 



2. Balfour, F. M. — '"'Anatomy and Development of Peripatus Capen- 



sis," 'Quart. Journ. Micr. Sci.,' vol. xxiii. 



3. Gaffron, E. — " Beitrage zur Anatomie u. Histologic v. Peripatus," 



' Schneider's Zoologische Beitrage,' Bd. i. 



4. Bourne, A. G. — " Contribution to the Anatomy of the Hirudinea," 



' Quart. Journ. Micr. Sci.,' vol. xxiv. 



