48 PROCEEDINGS OF THE ACADEMY OF [Vol. LXXIV 



Genus HELICINA Lamarck. Tropical America. 

 Subgenus TRISTRAMIA Crosse. Mainland. 

 ion ( )\ vrhombus C. and E. Mexico to South America. 



Oxyrhombus Crosse and Fisher (1893). Type (now chosen) H. amoena 



(1849). Honduras. 

 Conr.nl run A. J. \Y. (1905). Type (by t autonomy )H. concentrica Pfr. 

 1849 1. Merida, Venezula. 



ctisalcata A. J. W. (1905). Tvpe (by tautonomy) H. punctisulcata 

 von Martens (1890). 

 Punctisulcata A. J. W. (1910). Corrected form of preceding. 

 CincteUa A. J. W. (1910). Type (by tautonomy) H. cinctdla Sh. (1852). 

 Mexico. Not CincteUa Monterosato (1884). 



H. cinctella cinctella Shuttleworth (1852). Orizaba. Mex. 



//. botteriana Pfr. (1856). Orizaba, Mexico. 

 ?H. cinctella bautistae A. J. W. (1910). Tabasco, Mex. 

 "H. panctisulcata punctisulcata von Martens (1890). Omiltem, Guerrero, 8000 ft. 



//. pwnclisalcata A. J. W. (1905). 

 ??H. punctisulcata zunilensis A. J. W. (1910). Zunil, Guatemala. 

 H. amoena Pfr. (1849). Honduras. (Mex. to Panama). 



II. pnrpnrcojltirii Mt relet (1849). Guatemala. 

 H. sowerbyana Pfr. (1849). Guatemala??? Victoria, Tamaulipas, Mex. (Pilsbry). 

 H. ghiesbreghti Pfr. (1857). Chiapas, Mexico. 



//. ghisbrechti, ghisbrecti, ghiesbrechti, ghisbreghti, auct. 



IV. H. sinuosa Sowerby (1866) and A. J. Wagner (1910) 17 . 



In this group, the radulae of H. amoena 18 , H. cinctella 11 *, and H. 

 concentrica, 20 have been examined. The radular formulae of all 

 three species is given in Table III, while that of H. amoena is 

 figured (Plate III, fig. 8; Plate IV, 15). Especially noteworthy 

 are the well-developed, sharp-pointed cusps on the A and C centrals, 

 and the numerous pointed cusps on the comb-lateral. The narrowly 

 reflected border of the accessory plate simply joins the outer 

 continuation of the cusp-bearing portion of the comb-lateral. The 

 "handle" of the comb-lateral had a peculiar lamellar thickening 

 where it crosses obliquely the basal, spoon-shaped portion on the 

 tooth. On superficial examination, this might easily be mistaken 

 for a wing to the accessory plate. 



Although there is considerable break between the radula of this 

 group and that of Oligyra s. s., the operculum shows intergrading 

 characters. The horny portion is Helicina-like in Oxyrhombus, 

 but the calcareous portion is usually somewhat thickened, especially 



'As pointed oul by yon Martens (1890), this is certainly not H. sinuosa Pfr. 

 L850). Wagner gol bis specimens from Sowerby and Fulton. 



Iried specimens; A. X. S. P. no. 114S2S; collected at Gualan, Guatemala, 

 by S. \. Rhoads. 



.' dried specimens; A. N. S. P. no. 14577; collected in Mexico, by Salle 



! alcoholic specimens; collected for Univ. of Mich. Museum, near La Fria, 

 • Tachira, Venezuela. 



V 



