348 PROCEEDINGS OF THE NATIONAL MUSEUM Vol.89 



which shows the beginning of the postnuclear sculpture. Postnuclear 

 whorls inflated, strongly rounded, marked by rather coarse, more or 

 less regular, retractively slanting, low, rounded axial riblets, wliich 

 are always broader than the spaces that separate them; in addition 

 to tliis there is an indication of rather broad obsolete spiral threads. 

 Suture narrowly channeled; periphery well rounded. Base short, very 

 broadly openly umbilicated, marked by the continuation of the axial 

 ribs and by mdications of obsolete spiral threads; the umbilical wall 

 is marked by the continuation of the axial riblets and by spiral tlireads, 

 which vary in number and strength in the two races here recognized. 

 Aperture broadly oval; peristome double, the inner and outer co- 

 extensive and fused, separated by a mere line except at the posterior 

 angle where the separation is a little more marked; the fusing of the 

 two peristomes is so complete as to lead one easily to mistake it for a 

 simple structure. Operculum typically annularid. 



This species comes from the environs of Guantanamo Bay and 

 extends eastward to the mouth of the Yateras River. 



KEY TO THE SUBSPECIES OF ANNULARIA (ANNULARISCA) AURICOMA 



Axial ribs depressed auricoma 



Axial ribs not depressed putre 



ANNULARIA (ANNULARISCA) AURICOMA AURICOMA ([Gundlach] Pfeiffer) 



Plate 42, Figures 4-6 



1859. Cydostoma auricomum [Gundlach] Pfeiffer, Malakozool. Blatter, vol. 6 



pp. 71-72. 

 1862. Choanopoma auricomum Pfeiffer, Novitates conchologicae, vol. 2, pp. 



194-195, pi. 51, figs. 19-21. 

 1920. Tudora (TudoreUala) auricoma Henderson and Bartsch, Proc. U. S. 



Nat. Mus., vol. 58, p. 76. 



Henderson and Bartsch gathered this subspecies in immense quan- 

 tities from the various digitations and rocky cliffs jutting out into 

 Guantdnamo Bay. Here specimens were found under rocks and other 

 objects, which sheltered them from the sun's rays and from hot winds. 



These gatherings present some interesting variations in size and 

 color and would furnish a splendid subject for a biometrist. 



Our specimens, gathered on a hillside 1 mile from the Amusement 

 House on the Boquer6n Trail, agree most nearly with Gundlach and 

 Pfeiffer's descriptions and measurements. One hundred of these 

 yield the following measurements: 



