THE CYOLOPHORID LAJSTD M0LLUSIK9 OF AMERIOA 199 



There are six additional lots in the collection of the National 

 Museum, as follows : U.S.N.M. No. 252579, 7 specimens from 6 miles 

 west of Puerto Cabello, Venezuela; U.S.N.M. No. 99535, 1 specimen 

 from Puerto Cabello ; U.S.N.M. No. 339944, 1 specimen from Patan- 

 emo, near Puerto Cabello ; U.S.N.M. No. 366506, 1 specimen from La 

 Guayra, Venezuela; The following lots are labeled merely "Vene- 

 zuela"; U.S.N.M. No. 356142, 3 specimens; U.S.N.M. No. 57767, 3 

 specimens. 



The retractive slant of the riblets at the periphery and unicolor 

 coloration distinguish this from all the medium-sized forms. 



APEROSTOMA (AUSTROCYCLOTUS) AULARI (H. B. Baker) 



Plate 27, Figixbes 12-14 



1923. Poteria (Neocyclotus) glaucostonia aulari H. B. Baker, Occ. Pap. Mus. 

 Zool. Univ. Michigan, No. 137, pp. 37-88, pi. 5, figs. K, L, M. 



Shell of medium size, helicoid, the early whorls pale orange-brown, 

 the last olivaceous. At irregular intervals there are axial bands of 

 brown, which give the shell a somewhat variegated pattern of 

 coloration. The nucleus consists of 1.8 small, well-rounded, smooth 

 turns; the postnuclear whorls are well rounded, bending downward 

 into the suture and appressed to the summit, the appressed portion 

 forming a slender raised thread, marked by the retractive and pro- 

 tractive ribbing characteristic of the group, which produces the 

 usual granulated pattern. Suture well impressed. Periphery obso- 

 letely angulated. Base moderately broadly umbilicated, well 

 rounded, and marked with the sculpture of the spire, but here the 

 granulation is a little more pronounced. The umbilical wall is free 

 of granulation, and shows mere lines of growth. Aperture circular ; 

 peristome simple, that of the inner lip somewhat thickened and re- 

 flected ; the outer sharp. There is a slight angulation at the posterior 

 angle. Operculum typically aperostomid, having about 6 whorls. 



The specimen figured, Acad. Nat. Sci. Philadelphia No. 140908, 

 comes from the edge of the Cerritos de Yumarito, near Quebrado 

 Seca, Estado Yaracuy, Venezuela. It measures : Height, 13.7 mm. ; 

 greater diameter, 21.0 mm. ; lesser diameter, 15.2 mm. 



In coloration this species reminds one of ^. (A.) Umellum, but it 

 is easily differentiated from this by having a much broader umbilicus 

 and in being less globular. 



APEROSTOMA (AUSTROCYCLOTUS) GLAUCOSTOMUM (Pfeiffer) 



Plate 27, Figxtees 1&-19 



1855. Cyclostoma {Cyclotws) glaucostomtim Pfeeffee, Proc. Zool. Soc. London, 



vol. 23, p. 103. 

 1858. Cyclotus glaucostom/us Pfeiffer, Monographia pneumonopomorum viven- 

 tium, vol. 2, p. 20. 



