652 bartsch: classification of helicinidae 



phoriis tantalus mansalayanus n. subsp. The type, Cat. No. 258762. 

 comes from Mansalay Bay, has 5.6 whorls, and measures: altitude, 6.4 

 mm.; greater diameter, 10.8 mm. 



From the island of Romblon we have seen several lots of shells which 

 agree with Geophorus tantalus Bartsch in size and general sculpture, 

 but the peripheral keel is wider and not limited on the basal side by an 

 incised line. A shallow depressed concave area separates the convex 

 portion of the base from the peripheral keel. This form also has the 

 whorls considerably more convex on the upper side than the shells of 

 Geophorus tantalus and the sculpture is very coarse, while in Geophorus 

 tantalus it is rather fine. I therefore feel that it is specifically distinct 

 from Geophorus tantalus and it may be known as Geophorus romhlonensis 

 n. sp. The type. Cat. No. 208246, has 5.3 whorls and measures: alti- 

 tude, 7 mm.; greater diameter, 11.5 mm. 



Group C 



Shell small, narrowly conic 



Shell with a deep umbilical pit pseudomphalus Mollendorff 



Shell without a deep umbilical pit. 



Shell with a strongly compressed peripheral keel 



cyrtopomus Mollendorff 

 Shell with a rounded peripheral cord. 

 Peripheral cord strong, coarse and wavy 



trochaceus calayanensis Bartsch 

 Peripheral cord well rounded, smooth. 

 Upper surface coarsely granular. 



Greater diameter 8.9 mm trochaceus palauiensis Bartsch 



Greater diameter 7.9 mm trochaceus marivelesanus Bartsch 



Upper surface finely granular. 



Shell elongate conic trochaceus trochaceus Mollendorff 



Shell broadly conic .... trochaceus nanus (Mollendorff) Wagner 



The small conic granulose Geophorus having an excavated columella 

 that forms a strong angle at its junction with the basal lip and lacking 

 spirally incised lines, fall readily into three divisions, which may be 

 considered species. One of these, Geophorus pseudomphalus Mollen- 

 dorff, has a strongly impressed umbilical pit. This is so far known only 

 from the environs of Sibul, Bulacan Province, Luzon. The second 

 species, Geophorus cyrtopomus Mollendorff, ranges through the moun- 

 tains of central Luzon at least from Montalban to Morong. It is 

 characterized by a decidedly compressed peripheral keel and decidedly 

 less elevated spire than the next species. The third species, Geophorus 

 trochaceus Mollendorff, has a much wider range in distribution and 



