220 PROCEEDINGS OF THE NATIONAL. MUSEUM Vol.89 



KEY TO THE SUBSPECIES OF RHYTIDOTHYRA BILABIATA 



Entire shell bright rose colored rosea 



Entire shell not bright rose colored. 



Early whorls only, bright rose colored. 



Later whorls with a rosy flush rosacea 



Later whorls without a rosy flush. 



Peristome white bilabiata 



Peristome buff aurantiaca 



Early whorls white. 



Shell small nana 



Shell not small straminea 



RHYTIDOTHYRA BILABIATA ROSEA, new subspecies 



Plate 18, Figure 2 



This subspecies ranges from La Minn westward to the Sierra aox 

 Ancon, where we have seen it from the Hoyo de Magdalena, in the 

 Costanera de San Vicente, then southward through the south side of 

 this range to the Sierra del Infierno. 



It is characterized by a bright rose color. It also has the axial ribs 

 less expanded at the edge and a little more distantly spaced than the 

 other races, and the spiral sculpture is emphasized, the combination 

 of the two forming a screenlike pattern. 



The type, U.S.N.M. No. 535505, has 5.2 whorls remaining and 

 measures: Length, 18.6 mm.; greater diameter, 12.2 mm.; lesser 

 diameter, 9.3 mm. 



RHYTIDOTHYRA BILABIATA ROSACEA, new subspecies 



Plate 18, Figure 5 



This subspecies centers about the region of Vinales. We have it 

 from the Sierra de Vinales, the Chorrera, the mogotes from Laguna 

 de Piedras, extending from the Mogote Puertecitas to Mogote de la 

 Rinconada. We also refer here, with some doubt, specimens from 

 Cayos de San Felipe. 



In this subspecies we have rosy early whorls, and the rest of the 

 turns are washed with pale rose color. The peristome is white. 



The type, U.S.N.M. No. 355142, comes from the Puerta del Ancon. 

 It has a little more than 4 whorls remaining and measures: Length, 

 18.2 mm.; greater diameter, 11.9 mm.; lesser diameter, 9.7 mm. 



The animal of this subspecies was described by Bartsch, from 

 specimens collected by him on the Chorrera, June 22, 1928, as follows: 

 Body ash gray, with numerous fine, smoky flesh-colored dots. Ten- 

 tacles bright orange, with pale red base. Foot short, deeply cleft in the 

 median line, smoky gray. The locomotion of the two sides is alternate. 



