|li PROCEEDINGS OF THE ACADEMY OF [Vol. LXXIV 



better development of the wing on the accessory plate, which is more 

 like thai of the subgenus Alcadia. The centrals are closer to those 

 of Oligyra s. s., as is also the comb-lateral. As shown in 

 The synoptic key, the especial characteristics of this group are: 

 the wing on the marginals, the increased number of teeth, and the 

 tendency for the cusps on the A-central to be reduced to a small 

 number at the extreme outer tip. This last character and the wing 

 mi the marginals, which is shown in the figure of 0. oweniana 

 coccinostoma (Plate V, fig. 24), separate Succincta from all other 

 groups. In 0. cacaguelita, the A-central has a triangular expansion 

 of the tip, similar to the other species, but the cusps are either 

 pracl ically absent or are very much worn in the species, as compared 

 to 0. f. strebeli, is probably correlated with the difference in size. 

 All of the species show a tendency to increase the number of the 

 cusps on the marginals very rapidly. 



0. cacaguelita is the only South American species that I can 

 place definitely in this group. The section Tamsiana, which Wagner 

 places very near his section Gemma, appears from the radula, and 

 also from the texture of the operculum, to be a section in Helicina. 



Subgenus ALCADIA Gray. West Indies to So. America. 



Alcadia Gray (1840). Type H. major Gray (1825). Jamaica. 

 Eucaladia, Eualcadia A. J. W. (1907). Type (used as Alcadia s. s.) H. 



major Gray. 

 Palliata A. J. Wagner (1907). Type (by tautonomy) H. palliata C. B. 



Adams (1849). Jamaica. 

 ?Hispida A. J. W. (1907). Type (by tautonomy) H. hispida Pfr. (1839). 



Cuba." 

 ? Intusplicata A. J. \V. (1907). Type (by tautonomy) H. intusplicata 



Pfr. (1850). Haiti. 

 Incrustata A. \V. (1907). Type (by tautonomy) H. incrustata "Gund." 



Pfr. (1859). Cuba. 



A. .1. W. (1907). Type (by tautonomy) H. sericea Drouet (1859). 



( 'avenue. 



Section Idesa II. and A. Adams. West Indies. 



Tdesa II. and A. Adams (1X56). Type (Fischer 1 ") H. rotunda d. Orbigny 

 (1845). Cuba. 



•'"' last three sectional names are included simply for completeness; they 

 may represent perfectly valid groups. 



I ischer (1885) names the type of the genus Helicina, and then gives', in 

 parentheses and without remark, examples of each group. However, he seems 



ike an attempt to name the types, as in the first group they are correctly 

 For this reason, I have chosen, as far as possible, his examines as types 

 oi each group. Emoda II. and A. Adams is an exception, as A. J. Wagner, con- 

 trary to his usual habit, uses this group in an emended sense. 



