BY H. LEIGHTON KESTEVEN. 635 



9. — Kesteven, H. Leighton. — The systematic position of Fossarina, Ad. & 



Ang., and of Fossarina varia, Hutton. Kecords Aust. Mus., iv., 1902, 



317-322. 

 10. — Lacaze Duthiees. — " L'Anatomie et 1' embriogenie des Vermets." Ann. 



Sci. Nat. Zool. 4e ser. xiii. 1860, 230, pi. 4, tig. 6. 

 11.— Montrouzieb. — Jour, de Conch, xxvii., 1878, 26, pi. iii., tigs. 3, 3a. 

 12. — Moore, J. E. S — " The Molluscs of the great African Lakes. No. iii. 



Tangdnyikia and Spekia.\ Quart. Journ. Micr. Sci. xlii., 1899. 

 13. Op. cit. No. iv. Nassopsis and BytJwceras. Loc. cit. 



1899, 187, et seq. 

 14. — Nevill. — Hand List of the Mollusca in the Indian Museum, 1884, 159. 

 15. — Pease.— American Jour. Conch., iii., 1867, 287; pi. 12, fig. 8. 

 16. — Pelseneer. — Introduction a I'etude des Mollusques, 1894, 57. 

 17. — Philippi. — Abbildungen Conchylien. Band iii., 1847, 17, Tab. vi., 



fig. 24. 

 18. — QuoY & Gaimard.- Voyage de I'Astrolobe. Zool. Tome iii,, 1855, 271. 



Atlas Moll., pi. 62, figs. 8-11. 

 19.— Smith, E. A.— Journ. Linn. Soc. Lond. Zool. xii., 1876, 552. 



20. Ann. and Mag. Nat. Hist., ser. 5, vi., 1880, 425. 



21— SouLEYET.— Zool. de la Bonite, ii., 1853, 551, pi. 33. 



22. — SwAiNsoN. — A Treatise on Malacology, 1840, 352. 



23.— Tenison- Woods. — Proe. Linn. Soc. N.S. Wales, i., 1876, 242-249. 



24.— Tryon.— Structural and Systematic Conchology, ii., 1883, 242. 



25. Manual of Conchology, ix., 1887. 



26.— Woodward.— Proc. Zool. Soc. Lond., 1859, 349, pi. 47, figs. 4, 4a, 4&. 

 27.— Smith.— Ann. and Mag. Nat. Hist., ser. 6, vi., 1890, 93. 



EXPLANATION OF PLATE XXX. 



Anatomy of Risella. 



Fig 1.— Digestive system. — buc, buccal mass, rad., radula. an., anus. 



m.gl., mucous gland, post. as., posterior oesophagus, neph., 



nephridium. liv., liver, sal.gl., salivary glands. crop, crop. 



r.b.o., reno-pallial orifice. int., intestine. h.-p.d., hepato- 



pancreatic ducts. 

 Fig. 2.— Circulatory system. — cten., ctenidium. br.v., branchial vein. 



osph., osphradium. nepli.v., nephridial vein. a.c.c.'c."c."' , 



branches of the posterior aorta, b. , right pallial artery, ant.aor., 



anterior aorta, nepli.^ nephridium. 

 Fig. 3. — Genitalia ( $ )• — A-., a spermatozooid. p., penis, v.d., vas deferens. 



neph., nephridium. gl., testes. 



