136 



BULLETdlN 181, UlSnTEiD STATEiS NIATTO'NIAL MUSIEUM 



cited below, together with those of a series of specimens obtained at 

 the same place : 



Small specimens come from Telescope Hill on the northeast coast, 

 U.S.N.M. No. 307501. Gerrit S. Miller, Jr., collected representatives 

 at Mount Pleasant at an altitude of 1,500 feet, U.S.N.M. No. 360782. 

 Professor Summers collected specimens at an altitude of 700 feet, 

 without mentioning specific locality, U.S.N.M. No. 356045. 



Cyclohidalgoa, new subgenus 



Aperostomas of helicoid shape with closely crowded axial riblets. 

 Type: Ape'Tostoma (Cyclohidalgoa) translucidum (Sowerby). 

 Distribution : Colombia, Venezuela, British Guiana, Trinidad, and 

 Margarita Island. 

 Guppy showed the radula formula to be 3 : 3 : 3 : 3. 



APEROSTOMA (CYCLOHIDALGOA) TRANSLUCmUM TRINITENSE (Guppy) 



Plate 18, Figuees 7-12 



1864. Cyclotus trinitensis Guppy, Ann. Mag. Nat. Hist., ser. 3, vol. 14, p. 245. 

 1923. Poteria trarrslucida trinitensis H. B. Bakeib, Occ. Pap. Mus. Zool. Univ. 

 Michigan, No. 137, pp. 31-33, pi. 5, figs. B and C. 



Baker, in discussing the mainland forms of this species, recognizes 

 the subspecific distinctness of the Trinidad race, stating, "Shell more 

 depressed ; suture distinctly impressed ; whorls convex." The group is 

 an exceedingly difficult one, the proper elucidation of which may be 

 furnished when enough anatomic data has been adduced. 



Guppy describes the Trinidad animal as follows: "The animal is 

 of a pinkish colour, which is most pronounced about the tentacles. 

 The eyes are small and black. The mouth is provided with an amber- 

 coloured, somewhat triangular mandible, divided into two parts by a 

 median fissure, from which diverge slightly curved rows of minute 

 denticulations strongly resembling the lingual teeth of some Helicidae. 



