30 COELOCENTRUM. 



Length 38, diam. 13, length of aperture 10, width 9 mm. 



Length 33, diam. 12-12%, length of aperture 8y 2 -9, width 

 7i/2-8i/ 2 mm. 



S. W. Mexico : Cerro de Plumas, near Puerto Angel, State 

 of Oaxaca, on the Pacific coast, in a dense tropical forest 

 (Hoge). 



Anisospira strebeli PFEFFER, Yerh. Ver. f. Naturw., Ham- 

 burg, 1887, p. 21.Eucalodium strebeli v. MARTENS, Biol. 

 Centr. Amer., Moll., p. 265, pi. 16, f. 31-34. 



Very variable in size and shape, as the measurements given 

 above indicate. These are chiefly taken from von Martens' 

 measurements of selected individuals out of a series of thirty. 

 The shell is much more solid than A. liebmanni, with far 

 coarser sculpture and different internal armature. More- 

 over, the taper above is less abrupt. In the larger, cylin- 

 drical shells the last four whorls are of about equal diameter, 

 the next earlier three taper, another whorl remaining, begin- 

 ning again the cylindrical shape of the young stage. In 

 small shells (33 mm.) the last three whorls only are equal in 

 diameter, three above them tapering, and the next earlier one 

 upright again. In the smaller examples there is a distinct 

 angle in front defining the base; in the larger ones this is 

 wholly obsolete. The aperture also varies in shape. 



Von Martens records a worn specimen, probably of this 

 species, found by Mr. W. Lloyd at Culata, near Manzanillo, 

 on the west coast of Mexico. 



Genus CGELOCENTRUM Crosse & Fischer, 1870. 



Cylindrella of earlier authors. Eucalodium, sect. 2, 

 CROSSE & FISCHER, Journ. de Conchyl. xviii, p. 22 (1870). 

 Ccclocentrum C. & F., J. de C. xx, p. 302, type C. turris Pfr. 

 (1872) ; Miss. Scient. Mex., Moll, i, p. 339. STREBEL, Beitrag 

 Mex. Land- und Siisswasser-Conchyl. iv, p. 56. von MAR- 

 TENS, Biologia Centrali Americana, Moll., p. 267. 



Shell rimate, cylindric-tapering or cylindric-fusiform, com- 

 posed of many closely coiled whorls, the early ones usually 

 self -amputated in adult shells, the body cavity plugged with 

 a, convex, granulose septum, the cavity of the columellar axis 



