THE NAUTILUS. 



VOL. XXVII. APRIL, 1914. No. 12 



A NEW CUBAN LAND OPERCULATE. 



BY H. A. PILSBRY. 



During a recent visit 10 Cuba Dr. Henry Skinner, in the intervals 

 of entomological researches, collected a few land shells. Some dirt 

 scraped up on the San Carlos Estate, near Guantanamo, contained 

 over twenty species of shells, including the following new species, 

 which is named in honor of Mr. Charles T. Ramsden, Manager of 

 the Estate, in acknowledgment of his attainments in Cuban ento- 

 mology, ornithology and conchology. 



The new species is by far the smallest cyclophoroid snail yet known 

 from Cuba, and is further of interest for the reason that it is a dis- 

 tinctly phylogerontic or aged form, such as the writer has found in 

 numerous other Antillean groups. The snail fauna of the West In- 

 dies contains many groups bearing the marks of old age, and in all 

 probability approaching extinction. Sometimes this is manifested 

 by extravagant development of spines, hollow ribs or knobs, often by 

 more or less uncoiling in the later stages of growth. Some other 

 families of the fauna show no signs of decadence. 



The systematic position of the new species is doubtful, since none 

 retained the operculum ; but it is evidently congeneric with the Hai- 

 tian shell described as Geratodiscus solutus Henderson and Simpson 

 (Nautilus XV, p. 73, pi. 5, figs. 1, 2). Both of these species seem 

 related to the Cyclotus minimus Gundl., of Pfeiffer (Mon. Pneumon. 

 Ill Suppl. 2, p. 16; Suppl. 3, p. 31.) which has been referred to 

 Crocidopoma, a subgenus of Aperostoma, but I believe incorrectly. 

 The operculum of C. minimus is extremely peculiar. The nucleus is 



