THE CYCLOPHORID LAjS^^D M01.LUSKS OF AMEiRICA 15 



The sculpture consists of retractively curved axial riblets that vary 

 materially in number and strength in the different subspecies. All 

 the races show irregularly distributed pitting, which produces an 

 appearance of drilling by some parasite or of partial decay. This 

 character shows a tendency toward approaching Farcimen {Farci- 

 men) alutaceum ([Menke] Pfeiffer), in which it reaches a maximum 

 development. Periphery well rounded. Base well rounded, or some- 

 what produced, narrowly umbilicated, with or without a limiting 

 umbilical carina. The umbilicus in most races is concealed by the 

 widely expanded and reflected inner peristome. Aperture large, sub- 

 circular. Peristome much thickened, expanded, and reflected, ex- 

 cept that of the parietal wall, always wider on the columella than the 

 rest, and narrow and somewhat excised on the parietal wall. At the 

 posterior angle of the aperture and at the posterior columellar ex- 

 pansion, the peristome is thickened into more or less of a knob, which 

 furnished the specific name hituherculatum. Operculum typically 

 farcimenid. 



The species appears confined to the southern part of the Province 

 of Santa Clara, where it reaches its maximum differentiation in the 

 Trinidad Mountain region. 



We are recognizing five subspecies: 



KEY TO THE SUBSPECIES OF FARCIMEN (FARCIMEN) BITUBERCULATUM 



Whorls strongly rounded. 



Shell unicolor bituberculatum 



Shell bicolor minor 



Whorls not strongly rounded. 



Axial ribs irregular, interrupted giganteum 



Axial ribs not irregular or interrupted. 



Axial riblets strong gutierrezi 



Axial riblets not strong crassum 



FARCIMEN (FARCIMEN) BITUBERCULATUM BITUBERCULATUM (Sowerby) 

 PlATE 3, FiGXJBES 10-12 



1850. Cyclostoma ^tuberculatum Sowekby, Thesaurus Conchyliorum, vol. 1, 

 Suppl., p. 164*, pi. 31a, figs. 290-291. 



This race was collected somewhere in the mountains of Trinidad, 

 Santa Clara Province. It differs from all the others in being much 

 slenderer, unicolor, and much more regularly conic, with the whorls 

 strongly rounded, in which respect it resembles F. {F. ) hUuberculatum 

 mmor (Kobelt). 



The specimen figured, U.S.N.M. No. 535901, is the only one we have 

 that agrees with Sowerby's figure. It was obtained by Dr. de la Torre 

 from the ancient collection of D. Tomas Iradi in Cienfuegos. It has 

 4.9 whorls remaining and measures: Height, 32.7 mm.; greater di- 

 ameter, 17.3 mm. 



