Note on the structure and relations of the kidney in 



Aplysia. 



By 

 J. T. Cunningham, B. A. 



Fellow of University College, Oxford. 



With piate 30. 



The notices which I liave been able to find in Zoological literature 

 on the kidney of Aplysia are scanty and somewhat obscure. Delle 

 Chiaje ^ describes the »triangulär gland« as large and pink in color ; he 

 says that its anterior border forms the boimdary of the pericardium, that 

 its left margin is reflected at the wall of the abdomen, while its right 

 circumscribes the bottom of the branchial cavity, and that its inferior face 

 is in contact with the intestinal tube. This description of the general 

 relations of the organ is to a great extent correct, though somewhat in- 

 complete. He then proceeds to discuss the function of the gland; he 

 says it was the opinion of Cuvier that in A. fasciata the triangulär 

 gland secreted the purple fluid, which the animai gives out and which in 

 his own opinion is derived from superficial small glands of the mantle : 

 the latter are violet in color, while the triangulär gland, when pressed 

 or cut, gives no trace of purple fluid and is itself of a pinkish white tint. 

 He mentions the fact, that in A. leporina, Cuvierana and Poliana the fluid 

 secreted by the superficial glands of the mantle, is white and viscous, 

 and then suggests that the function of the triangulär gland is to scerete 

 the »bony molecules« of the shell, both gland and shell being absent in 

 Notarchus. The interesting hypothesis of the great Neapolitan Natura- 

 list would derive some support from the latter fact, if it were true ; but 

 although Notarchus does not possess a shell, its renal organ is a glaud 



1 Delle Chiaje, Animali senza vertebre del Regno di Napoli. Napoli 1841. 

 Voi. II p. 64. 



