194 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 85 



neither of wliicli would seem to be effective in the transportation of 

 members of tlie groups under discussion, which we believe are largely 

 segregation i)roducts of a once continuous widely spread fauna. 



Western Cuba Avas subjected to many vicissitudes during Tertiary 

 times and even during the yesterdays of the Pleistocene, for vacillating 

 ocean levels from time to time changed this end of the island from 

 a continuous land mass to an arcliipelago of islands, eliminating the 

 lowland faunas and confining the survivors to the influence of their 

 restricted island habitats. All of which presents a fascinating his- 

 tory that our studies are slowly revealing. 



We shall have occasion to call attention to some of these problems 

 under the diverse groups here presented and discussed. 



These Cuban mollusks have received the attention of many of the 

 naturalists who have visited the "Pearl of the Antilles," or discussed 

 its faunas from the days of Humboldt and Bonpland to date. Their 

 listing displays such names as Sagra. d'Orbigny. Pfeiffer, Gundlach, 

 Otto, Wright, Poey, Gould, Arango, Morelet, Sagebien, Henderson, 

 Simpson, Clapp, Pilsbry, Barbour, Miner, Welch, Lowe, Allen, Clench, 

 Rehder, Hermano Leon, Father Roca, and de la Torre and his students, 

 among them especially Rodriguez, Aguayo, Ramsden, Bermudez, Por- 

 tuondo, Moreno, and Jaume. To these should also be added a host 

 of de la Torre's friends, too numerous to mention, who have lent a 

 hand in this enterprise, as well as many field men commissioned from 

 time to time by him to explore specific regions in need of investigation. 



Looking over the field as a whole we may say that the major discover- 

 ies in our field fall to the credit of de la Torre, Gundlach, Pfeiffer, 

 Sagra, Poey, Henderson, and Bartsch, the efforts of Torre, Henderson^ 

 and Bartsch being directed toward the specific exploration and eluci- 

 dation of the island fauna. 



The present paper is a resumption of the studies by Henderson and 

 Bartsch published in 1920, "A Classification of the American Opercu- 

 late Land Mollusks of the Family Annulariidae," ^ Mr. Henderson's 

 untimely death interrupted this effort, which is now resumed by his 

 devoted friends. 



Subfamily Chondropominae Henderson and Bartsch 



1920. Chondropominae Henderson and Bartsch, Proc. U. S. Nat. Mus., vol. 58, 

 p. 59. 



Annularid mollusks whose shell ranges in form from turbinate to 

 elongate-conic. The axial sculpture may consist of strong ribs or 

 range from these to slender, almost lamellar riblets, or it may be re- 



1 Proc. U. S. Nat. Mus., vol. 58, pp. 49-82, 1920. 



