104 



BULLETIN 192, UNITED STATES NATIONAL MUSEUM 



174 on the last. These riblets are not all of the same strength or spacing, 

 the larger ones being usually more distantly spaced than the slender ones, 

 which, as a rule, follow them and are more closely spaced. The riblets 

 become expanded at the summit where two, three, four, or even more 

 may become fused into a conspicuous tuft. The spiral sculpture consists 

 of low, rounded threads, of which 7 occur on the first of the re- 

 maining turns, 9 on the second, and 13 on the rest. The junctions of the 

 axial riblets and spiral threads form slender, elongated nodules having 

 their long axis parallel with the ribs, while the spaces enclosed between 

 them are narrow rectangular shallow impressed areas. Suture channeled. 

 Periphery inflated, well rounded. Base short, rounded, broadly and openly 

 umbilicated, marked by 10 spiral cords and the continuation of the axial 

 ribs. Within the umbilicus additional spiral cords are present. Last 

 whorl solute for about one-tenth of a turn. Aperture broadly oval; 

 peristome double, the outer projecting narrowly, except on the inner lip, 

 where it is much broader; the inner is exserted and slightly reflected. 

 Operculum typically haitipomid. 



The type (U.S.N.M. No. 355334) was collected by John B. Hender- 

 son and the author at St. Marc. It has a little over 3 whorls and meas- 

 ures: Height, 16.3 mm.; greater diameter, 9.4 mm.; lesser diameter, 

 8.3 mm. 



Twenty additional specimens (U.S.N.M. No. 355302) from the type 

 locality yield the following average measurements : 



The species appears to range from St. Marc south through the Cul- 

 de-Sac region. 



This subspecies shares the expanded inner lip of the outer peristome 

 with H. catalinense, from which its much larger size and stouter form 

 will readily distinguish it. 



U.S.N.M. No. 355303 contains 14 specimens collected by Henderson 

 and Bartsch at 200-300 feet altitude at St. Marc. 



U.S.N.M. No. 392346 contains 52 specimens collected by Bartsch on 

 bluffs I mile north of St. Marc. 



U.S.N.M. No. 355335 contains 13 specimens collected by Henderson 

 and Bartsch at St. Marc. 



U.S.N.M. No. 355337 contains 10 specimens collected by Henderson 

 and Bartsch at Kilometer 81. 



U.S.N.M. No. 392871 contains 10 specimens collected by Bartsch on 

 top of the hill before reaching the Artibonite Valley. 



