252 BULLETIN 192, UNITED STATES NATIONAL MUSEUM 



spire. Aperture oval; peristome double, the outer moderately, broadly 

 expanded, thick, marked by feebly developed, concentric laminae; the 

 inner slightly exserted, decidedly reflected and fused with the outer for 

 the major portion. Operculum typically colonellid. 



This species comes from San Salvador, where two subspecies appear 

 to be present, one of which occupies the portion bordering the inner 

 lagoon, while the other seems restricted to the beach in and about Cock- 

 burn Town. 



KEY TO THE SUBSPECIES OF OOLONELLA WATLINGENSIS 



Denticles at the summit consisting of fused axial riblets watlingensis 



Denticles at the summit not consisting of fused axial riblets henryi 



colonella watlingensis watlingensis (dall) 



Plate 38, Figure 7 



1894. Chondropoma ivatlingense Dall, Bull. Mus. Comp. Zool., vol. 25, p. 118, 



fig. 6. 

 1920. Chondropoma (Chondropomoru^) watlingcnse Henderson and Bartsch, 



Proc. U. S. Nat. Mus, vol. 58, p. 61. 



This subspecies occupies the lagoon area of San Salvador, or Watling, 

 Island. It differs from C. w. henryi in having the denticles at the summit 

 of the whorls usually produced by the fusion of a number of the axial 

 riblets. The shell is also a little more elongate. 



The type (U.S.N.M. No. 355930) conies from the shores of Lake 

 Ferdinand, the smaller of the two lagoons within the island. It has a 

 little more than 4 whorls remaining and measures: Length, 8.1 mm.; 

 greater diameter, 3.8 mm. 



U.S.N.M. No. 127499 contains 4 topotypes from the same source. 



COLONELLj\ watlingensis HENRYI, new subspecies 



Plate 38, Figure 9 



This subspecies was collected in large numbers by the author and 

 his son, Henry, for whom it is named, on the seaside shores about Cock- 

 burn Town, San Salvador (Watling Island). 



It is easily distinguished from the typical race by the stronger axial 

 ribs, which become expanded into hollow denticles at the summit and 

 therefore are not the fusion product of several of them. The race also 

 seems to have narrower v/horls and appears of general darker colora- 

 tion. 



The type (U.S.N.M. No. 366526) comes from Cockburn Town. It 

 has a little over 3 whorls and measures : Length, 7.3 mm. ; greater di- 

 ameter, 3.4 mm. 



U.S.N.M. No. 360487 contains 47 topotypes from the same source. 



U.S.N.M. No. 360301 contains 211 specimens collected by H. and P. 

 Bartsch at Riding Rock, San Salvador. 



U.S.N.M. No. 360333 contains 7 specimens collected by H. and P. 

 Bartsch from North Road, San Salvador. 



