Occasional Papers of the Museum of Zoology 29. 



curs as an almormality in other species. The type locaHty is. 

 Minas Geraes, Brazil. It is just possible that this species is 

 related to Cychstoma disjunctum Moricand (1846), also froni 

 Brazil.^ 



The opercula of (*) Cyclostoma psilomitum Pfr. (1851) 

 from Venezuela. Apcrostoma connivcns H. Adams (1866) 

 from Eastern Peru, and Cyclostoma distiiictum Sowerby 

 (1843) from the Bay of ^lontija. Panama, are unknown, but 

 these Crocidopoma-like species certainly do not ])elong in Neo- 

 cyclotus. (*) C yclotus coopcri Tryon (1863) from ]\Iazatlan, 

 Mexico, is clearly an Amphicyclotus. close to A. lutcsccus- 

 (Pfr., 1851); while (*) Cyclotus boucardi Angas (1878) 

 from San Carlos, Costa Rica, not A. boucardi (Pfr., 1856) is 

 evidently close to A. poiidcrosus ( Pfr., 1851). ( !) A', injlatus, 

 from Santa Marta, and ( !) K. solutus. from New Granada, 

 both "Mousson" Kobelt and Moellendorff ( 1897, Nach. D. 

 Malac. Ges.) appear to be nude names, as is also ( !) iV. 

 chfvsacmc "Bartsch" Fluck (1906, Xaut.), from Wani, Nic- 

 aragua. Cxclostoma sutnralc and C. discoidcum, both Sower- 

 by (1843). are extralimital species, incorrectly cited from 

 Demerara, Guiana. 



The mainland species of the subgenus Neocyclotus may l^e 

 divided into four, quite distinct groups, as follows : 



I. Group of Cyclostoma trauslucidum Sowerliy (1843). 

 Shell turbinate, usually unicolor; growth lines very prominent 

 and often crossed by sjjiral striations ; basal portion of peri- 

 stome usually slightly emarginate. ^Mexico to Trinidad and 

 Peru. 



•'"' C disji-nctiivi is the type of Cyclopoma Troschel (1847), not Agas- 

 si?. (1833); tliis preoccupied name was inadvertently omitted from m>^ 

 1922 paper. It is a synonym of Amphicyclotus. 



