118 BULLETIN 181, UNTTEID STATES NtATTOOSRAL MUSEHCIM 



POTERIA (CYCLOBAKERIA) WELCHI, new species 



Shell of medium size, helicoid, covered with a chestnut-brown 

 periostracum. The nucleus consists of a single well-rounded, smooth 

 turn. The postnuclear whorls are marked by slender, rather closely 

 approximated, slightly retractively slanting, hairlike riblets, which 

 become decidedly irregular on the last whorl. Beginning with the 

 third whorl rough wrinkles make their appearance on the upper 

 surface of the whorls. These are strongest near the summit and extend 

 protractively slanting toward the periphery, which they do not quite 

 reach. The spaces separating these ridges are almost as wide as the 

 ridges. Suture well impressed on all but the last turn. Here the 

 summit is appressed and renders the suture less conspicuous. Peri- 

 phery well rounded. Base moderately broadly umbilicated, well- 

 rounded, and provided with a strong keel at the outer edge of the 

 umbilicus. On the umbilical side of this keel the shell is decidedly 

 excavated. From the umbilical keel protractively curved ridges 

 radiate toward the periphery. These are very pronounced in the 

 typical race and feebly expressed in the subspecies P. (C.) welchi 

 taylori. The posterior portion of the base is smooth, except for indi- 

 cations of spiral lines. Aperture circular, decidedly oblique, pro- 

 tracted into an angle at the posterior angle. Operculum typically 

 cyclobakerid. 



I am recognizing two subspecies, which the following key and 

 descriptions will help to differentiate : 



KEY TO THE SUBSPECIES OF POTERIA (CYCLOBAKERIA) WELCHI 



Pits outside of umbilical keel strong welchi 



Pits outside of umbilical keel not strong taylori 



POTERIA (CYCLOBAKERIA) WELCHI WELCHI, new subspecies 



Plate 16, Figures 1-3 



The typical race was collected by Welch on Dolphin Mountain, 

 Jamaica, at an altitude of 1,200-1,450 feet. This mountain is located 

 in the central western portion of Westmoreland Parish. 



This subspecies differs from P. {C.) to. taylori in having the pits 

 outside of the umbilical keel on the base very deep and the ridges 

 bordering these very pronounced. Both of these characters are 

 absent in taylori. 



The type, U.S.N.M. No, 535977, from Dolphin Mountain, Jamaica, 

 has 5.1 whorls and measures: Height, 20.0 mm.; greater diameter, 

 26.0 mm.; lesser diameter, 18.9 mm. 



