634 NOTES ON PROSOBRANCHIATA, 



remains to be ascertained, so insufficient have purely conchological 

 characters proven. 



Nassopsid.e. 



The family here proposed contains but one species, Ji^assopsis 

 nassa, Woodward (86, 27), one of the unique "Halolimnic" mollusca 

 of Lake Tanganj^ika. The anatomy has been very thoroughly 

 worked out by J. E. S. Moore (13), but this writer has viewed the 

 characters of the species of the Halolimnic fauna from so prejudiced 

 a standpoint that, instead of discussing their affinities, he has 

 exerted all his ability to prove that they are surviving Jurassic 

 archetypes. To such lengths is this conviction carried that the 

 arguments used tend, in some instances, to weaken the undoubt- 

 edly correct theor}^ that the lake has been an arm of the sea in 

 early geologic times. 



In the present instance no definite opinion as to the relation- 

 ship of the genus is given, though it is vaguely compared with 

 the Strombidae, Paludina and Littorina. A careful weighing 

 of its characters, however, it is here contended, shows its relation- 

 ship to be with the Littorinidae. 



BiBLIOGEAPHY. 



1. —Adams, H. & A.— Genera of Recent Mollusca, i., 1854, 316. 



2.— DiGBY, Lettice. — " On the Structure and Affinities of the Tanganyika 



Gasteropods, Chytra and Limnotrochus" Journ. Linn. Soc. Lond. 



Zool., xxviii., 1902, 434, ct seq. 

 3. — Fischer.— Journal de Conchyliologie, sxvi., 1S78, 212; xxvii., 1879, 29, 



pi. iii., fig. 4. 



4. Manuel de Conchyliologie, 1887, 709. 



5_ — Gibson, R. J. Hakvey. — " Anatomy and Physiology of Patella valgata " 



Trans. Roy. Soc. Edin., xxxii., 1885, GOl-638. 

 6._GouLD.— Proc. Boston Soc, iii., 1849, 118. United States Exploring 



Expedition (Wilkes), xii., 1852, 184, figs. 215, 215a, 2156. 

 7.— Hedley, C. — Mem. Aust. Mus., iii., pt. 7; "Mollusca of Funafuti, 



1899, 424. 

 8. "A Revision of the Types of the Marine Shells of the 



Chevert Expedition." Records Aust. Mus., iv,, 1901, 121. 



