176 MANUAL OF THE MOLLUSGA. 



sp. C. elegans, is found on calcarious soils ; it ranges to the Canaries and 

 Algeria, and occurs fossil in the newer Tertiaries. Nearly half the species 

 have the whirls spirally keeled, and have heen distinguished under the name 

 Tropidophora, by Troschel. They are found in Madagascar and the adjacent 

 islands and coast of Africa. Fossil, 20 sp. Eocene, Europe. 



Sub-genera. Otopoma (foliaceum), Gray. Shell sub-globose, umbili- 

 cated ; peristome with an ear-like process covering part of the perforation. 

 Distr. 15 sp. Arabia, Madagascar, China, New Ireland. 



Choanopoma (lincina) Pfr. Shell often a little decollated; peristome 

 usually double, the outer edge angularly expanded. Lincina (labeo) Br. 

 has the last whirl produced. Jamaida (anomala) C. B. Adams, has the oper- 

 culum convex. Distr. 70 sp. W. Indies, and a few in Tropical America. 



Cistula, (fascia), Gray. = Tudora (megacheila), Gray. Shell ovate or 

 elongated, apex usually decollated, peristome free; operculum with a thin 

 shelly outer coat. Chondropoma (semilabre) Pfr. differs in the operculum 

 being "sub-cartilaginous." Distr* About 70 sp. W. Indies; Tropical 

 America, 8 sp. 



Realia (hieroglyphica), Gray. = Hydrocsena (part) Parreyss, Ompha- 

 lotropis, Pfr. Liarea (Egea), Gray. Bourciera (helicinseformis) Pfr. Shell 

 turrited or turbinate, perforated; peristome simple, straight or expanded; 

 operculum pauci-spiral, horny. Distr. 17 sp. Canaries,? Mauritius, Pacific 

 Ids. (Ecuador, Bourciera.} 



Pomatias (maculatum), Studer. Shell slender, transversely striated; 

 peristome reflected; operculum cartilaginous, concamerated within. Distr. 

 10 sp. S. Europe ; Corfu. 



? FERUSSINA, Grateloup. 



Etym. named in honour of Baron Ferussac. 



Type, F. anastomseformis, Gr. Syn. Strophostoma, Desh. 



Shell rounded, depressed, umbilicated ; whirls transversely striated above, 

 spirally keeled below ; aperture turned obliquely upwards, peristome simple, 

 Operculum. ? 



Fossil, I sp. Miocene . Dax ; Turin. 



CYCLOPHORUS, Montfort. 



Etym. Cyclos, circle, phoreus, bearer. 



Type, C. involutus, PL XII. fig. 41. 



Shell depressed, openly umbilicated ; aperture circular; peristome con- 

 tinuous, straight or expanded; epidermis thick; operculum horny, many- 

 whirled. 



Animal with long, slender pointed tentacles ; foot broadly expanded, not 

 grooved. 



Distr. About 90 sp. India, Philippines, New Zealand, Pacific Ids. Tro- 

 pical America. C. gibbns, Fer. (Alycaeus, Gray) has the last whirl distorted. 



