THE CYCLOPHORID LAI^D MOLLUSKS OF AMERICA 127 



APEROSTOMA (CYCLADAMSIA) RUBER PRETIOSUM (Chitty) 



Plate 17, FiGxmES 25-27 

 1857. Cyclotus pretiosus Chitty, Proc. Zool. Soc. London, vol. 25, p. 153. 



In type of sculpture this subspecies corresponds in every way with 

 that of typical ruber. It differs from it mainly in its much more 

 diminutive size. 



The specimen figured, U.S.N.M. No. 400998, was collected by C. E. 

 Orcutt on a tall hill near Maggotty, St. Elizabeth Parish, Ja- 

 maica. It has 3.4 whorls remaining and measures : Height, 8.5 mm. ; 

 greater diameter, 15.0 mm. ; lesser diameter, 11.2 mm. 



In his description Chitty cites New Hope, Westmoreland, as type 

 locality. We have not seen specimens from New Hope, but we do 

 have lots from three adjoining parts of St. Elizabeth Parish, namely, 

 Maggotty, Cheltenham, and a road cut 4 miles north of Black Kiver. 



APEROSTOMA (CYCLADAMSIA) BAIRDIANUM (Chitty) 



Pate 17, Figures 28-30 



1857. Cyclotus lairdianus Chitty, Proc. Zool. Soc. London, vol. 25, p. 153. 



Shell helicoid, of medium size, "of rich red brown color, with some^ 

 times a lighter band at the periphery and around the umbilical keel, 

 yellowish at the suture of the last whorl" (Chitty). The nucleus 

 consists of about one turn. The first postnuclear whorl is marked 

 by retractively curved axial riblets, which are a little broader than 

 the spaces that separate them. The whorl succeeding shows lines of 

 growth, which are strongest at the summit, and malleations on the 

 rest of the shell. This type of sculpture continues to the aperture, but 

 becomes intensified and developed more or less into strong wrinkles. 

 Suture moderately impressed. Periphery well rounded. Base well 

 rounded, openly umbilicated and marked with a very strong keel at 

 the outer edge of the umbilicus and decidedly pinched in below the 

 keel in the umbilicus. The base is marked by pittings which extend 

 to the periphery. On the last one-fifth of a turn there are also 

 strong decidedly retractively curved axial cords, which are separated 

 by spaces about as wide as the cord. These vanish before reaching 

 the periphery. The umbilical wall is marked by irregular lines of 

 growth which render it rather rough. Aperture obhque, circular, 

 with a feeble angle at the posterior angle, slightly emarginated below 

 the summit on the outer lip and slightly excavated on the columellar 

 wall. Operculum typically cycladamsid. 



Chitty failed to cite any locality with his description. Three 

 specimens before me from the Adams collection mixed with "6^. 



