42 



lakes, (2) an extremely large proportion of them are not found 

 elsewhei-e, (3) certain forms (notably Gasteropoda) are considered 

 to have a marine-like appearance. The view previously put 

 forward which regarded the lake as the remains of an old Jurassic 

 sea was considered untenable, since many of the types thought to 

 be marine and primitive belong to essentially fresh-water groups 

 ^nd show signs of specialisation. The Jurassic hypothesis proves 

 likewise incompatible with recent geological evidence. After 

 discussing vaiious other theories, it was suggested that Tan- 

 ganyika probably owes its remarkable organisms to a prolonged 

 period of isolation — coupled, perhaps, with the effect of an 

 increased salinity which isolation would involve. 



In the absence of the Authors, Mr. Henry F. Carter's paper 

 on •' Descriptions of the Adult, Larval, and Pupal Stages of a 

 new Mosquito from Lord Howe Island, South Pacific," and Prof. 

 0. L. Bo'tenger's paper on " Filariid Worms from Mammalia 

 and Bircls in the Society's Gardens, 1914-1915," were taken as 



The next Meeting of the Society for Scientific Business will 

 be held on Tuesday, February 8th, 1921, at 5.30 p.m. 



A notice stating the Agenda for that Meeting will be circulated 

 early in February. 



. The following Papers have been received : — 



C. F. SoNNTAG, M.D., Ch.B., F.Z.S . 



The Comparative Anatomy of the Tongues of the Mam- 

 malia. — II. Fam. Simiidfe. 



oo 



Augusta Arnback Christie-Linde. 



On the Reproductive C)rgans of the Ascidian Kilkenthalia 

 horealis Gottschaldt. 



