46 COELOCENTRUM, SECT. LIOCENTRUM. 



subangular-piriform ; peristome white-calloused, interrupted, 

 shortly reflexed, the columellar margin subvertical, within 

 slightly folded above. Length 22y 2 , diam. 8y 2 mm.; oblique 

 length of aperture 5, width 4 mm. (Pfr.) 



Cyl. liidersi PFR., Monogr. Hel. Viv. iv, p. 712 (1859) ; 

 Malak. Bl. xxiii, p. 217. 



Said to be from S. Domingo (Liider's coll.). In his review 

 of the Monographia Pfeiffer states that this species " differs 

 from the rest of the Coelocentrums in that the hollow internal 

 column shows also an external perforation at the base. ' ' The 

 species has not been figured, and the interrupted peristome 

 seems an unusual character for this genus. If really a Coelo- 

 centrum, as Pfeiffer states, the locality, given with doubt by 

 Pfeiffer, must be erroneous. 



Section LIOCENTRUM Pilsbry, 1902. 



This group differs from typical Ccclocentrum in wanting 

 riblets or lamellae upon the smooth internal pillar, which may 

 be either cylindric or swollen within each whorl. Type C. 

 filicosta ( Shuttl. ) . 



See under C. filicosta for description of the apex (pi. 18, 

 fig. 38). 



I. Rather small species, diam. 6y 2 -9y 2 mm., length 22-30 

 mm.; ribs rather widely spaced, the intervals spirally 

 striate. 



a. Internal pillar swollen within each whorl; riblets 

 well spaced. C. filicosta, p. 47. 



&. Internal pillar cylindric; riblets a little closer. 



C. crosseanum, p. 47. 



II. Larger forms, diam. about 14 mm. ; costula? of the outer 

 surface numerous and feeble. 



C. chain />ioiii, p. 49; C. datli rat-urn, p. 49. 

 Strebel has already remarked that in this group there are 

 some opaque white lines in the substance of the smooth col- 

 umn, taking the place of costulrc on the internal pillar. 



In the last two species the internal column is described as 

 with very faint costulse, and in championi at least it is figured 

 1)\ von Martens as remarkably slender, almost like that of 

 Kucaludinm (pi. 9, f. 14). 



