242 



BULLETIN 192, UNITED STATES NATIONAL MUSEUM 



lesser diameter, 4.1 mm. I collected this and 522 other specimens 

 (U.S.N. M. No. 360494) on Bobs Key, in Lake Ferdinand, i.e., the 

 smaller of the two interior lakes, San Salvador. 



One hundred additional specimens yield the following average meas- 

 urements : 



I take pleasure in naming this race for my son, who assisted me in 

 the exploration of San Salvador, 



OPISTHOSIPHON (LEPTOPISTHOSIPHON) COL,ONI COLONI, new subspecies 



Plate 37, Figure 7 



This subspecies differs from O pisthosiphon (Leptopisthosiphon) coloni 

 henryi in having the axial riblets much less strongly developed, and from 

 0. (L.) c. ferdinandi in having the umbilicus closed. 



The type (U.S.N.M. No. 355426) was collected by the U. S. Bureau 

 of Fisheries near Riding Rock near Cockburn Town, San Salvador, 

 Bahamas. It has a little over 4 whorls and measures: Length, lo.i mm.; 

 greater diameter, 4.7 mm. ; lesser diameter, 4.0 mm. 



U.S.N.M. No. 132966 contains 4 topotypes from the same source. 



U.S.N.M. No. 360486 contains 112 specimens collected by P. and H. 

 Bartsch on rocks at Cockburn Town, San Salvador. 



A hundred additional specimens, out of a lot of 426 specimens 

 (U.S.N.M, No, 360300), collected by the author and his son at Riding 

 Rock, Cockburn Town, on the seaside shore of the island, yield the fol- 

 lowing average measurements : 



OPISTHOSIPHON (LEPTOPISTHOSIPHON) COLONI FERDINANDI, new subspecies 



Plate 37, Figure 5 



1894. Chondropoma rawsoni Dall, Bull. Mus. Comp. Zoo!., vol. 25, p. 117; not 

 Chondropoma rawsoni Pfeiffer, 1867. 



This race is differentiated from the other two by having the inner 

 peristome not reflected over the umbilicus so as to cover it, but extended 

 outward as a flap. 



