34 LAND AND FRESHWATER 



Tropidophora, with Leonia &c., and Otopoma have long diverted 

 from some earlier form. They both now occupy the two well- 

 defined geographical areas of South Africa and Madagascar on one 

 side, Eastern Africa north of the Equator, Arabia, to shores of the 

 Western Indian Peninsula on the other. Cyclostoma, so distinct 

 from them, occupies the European area and eastward into Asia as 

 far as the Caspian and Persia. 



It is exceedingly doubtful if true Cyclostoma extends to the West 

 Indies, although I notice Nevill includes hanlsianum and jai/anxm 

 in his ' Hand-list,' pp. 303 & 304. The teeth of both are given by 

 Troschel on plate iv. figs. 15 & 17, showing they are of the character 

 of the other West-Indian species of Choanopoma. If I am right in 

 my conjecture that the outside tooth in Tropidophora is a compound 

 one, then, allowing the mind to exercise a little imagination, we 

 may take the radula of Jdelkina and compare it with Tropidopdiora 

 unifasciata, and regard the large notched and solid tooth no. 4 of 

 the first to be analogous with the inner large notched tooth no. 3 

 of the second ; while the numerous outermost close-set teeth of 

 Helicina correspond with no. 3' of Tropidophora. The likeness can be 

 strengthened if we imagine these outermost teeth in Helicina to be 

 the upper margin of one wide elongate plate. The outermost teeth 

 of Chon<(ropoina show also, by the deep cleft edges, a growing 

 together of what was once a series of separate teeth. It indicates, 

 going back into the long eras of development, how far apart and 

 how very dift'erent has been the line of descent of the Cyclostomidae 

 and the Cyclophoridac, the latter lying in the direction of the Lit- 

 torinidae. We know nothing of the early stages of life of these 

 genera of the Cyclostomidic. Judging from the fact that the large 

 Bulimns of Aden is viviparous, it is very probable that Otopoma of 

 so dry and arid an island as Socotra is the same. Eggs laid would 

 be desiccated, and the only chance of survival would be develop- 

 ment in the body of the mother, or within the branchial chamber, 

 until large enough, with a fall of rain, to crawl about and feed 

 themselves. Very little is known, so far as I can ascertain, of the 

 eggs and development of Cyclostoma or Cyclopjhoras ; it is a branch 

 of the history of these genera that requires investigation, as it 

 may tell us much concerning their relationships. 



Subfamily Pupinin^. 

 Genus Pfpina. 



Pupina, M. Vignard, Ann. des Sci. Nat. vol. xviii. p. 439 (1829). 



Type P. Iceraudrenii, Vignard, pi. xi. figs. 1 & 2 (a very 

 good figure). 

 Original description : — " Coquille turhinee, ovale, ouver-ture pro- 



fondement fendiie ; columelle recourhee, tronquee." New Guinea. 



Moulinsia, Grateloap, Ann, Soc. Linn. Bordeaux, xi. p. 429 (] 840). — 

 Type M. nunezii, Sow. : from the Philippines. 



