Occasional Papers of the Museum of Zoology 15 



from Cumana, Venezuela (L 11, 64); O. dysoiii barbata 

 (Guppy, 1864) from Trinidad; O. (Sitcciiicta) cacagiiclita 

 (Pilsbry and Clapp, 1902) from Cacaguelita, vSanta Marta 

 Mts., Colombia (I^ 11, 74); and 0. ( /) pcUucida { Sowerby, 

 1842) from Surinam, Guiana. 



The radular formula of a dried specimen of O. dysoiii bar- 

 bata (A. N. S. P. 14917. Trinidad, Swift Collection) is given 

 below and samples of the teeth are figured (fig. iii-12). The 



Uncini with 

 A B C D 3-cusps ; 4-cusps Total Each row 

 O. dysoiii barbata 3-4 5 4 7-8 8 4 64 139 



O. rufa 3-4 5 4-5 7-8 6 4 75 161 



centrals are quite similar to those of (Jligyra s. s.. but the shell 

 characters approach those of Alcadia ; Analcadia is perhaps 

 best retained as a subgenus between the two sul^genera Oligyra 

 and Alcadia. The radular formula of two dried specimens of 

 O. [Analcadia) rufa ( Pfr., 1857) from Yuma River, Haiti 

 (A. N. S. P. 63953), i-'' given for comi)arison (fig. iii-ii). 

 The inner marginals have two large cusps and a vestigial, outer 

 one, very much as in Idesa and Alcadia s. s. ( )therwise, this 

 radula is very similar to that of the vSouth American species. 



The radular formula and prol)al)le position of O. cacaguelita 

 have been discussed in a former paper (1922). I have not 

 seen specimens of O. pellucida. but it also appears to belong 

 in Succincta. However, other writers have noted its similarity 

 to H. tamsiana Pfr. 



For comparison with the above, the radula of O. (Alcadui 

 Idcsa) rot inula ( Orbigny, 1845) from Marianao, Cuba, is fig- 

 ured ( fig. iii-13). The formula is given in another paper (1922). 

 It agrees with Alcadia s. s. in the shape of the centrals, but the 

 pointed cusps of the D-plate resem])le those of Sericea or Anal- 

 cadia. The first marginal is practically bicuspid. 



