EUC ALODIUM. 7 



form, compressed fold. Aperture slightly oblique, irregu- 

 larly oval, angular above; peristome continuous, reflexed 

 throughout, the right margin thickened, regularly arcuate, left 

 margin sinuous. Length 55, diam. 15, length of aperture 13, 

 width 101/0 mm. (Pfr.). 



Mexico (Cuming) ; Tabasco (Berendt) ; Chiapas (Bland). 



Cylittdrella mexicana ' Cuming,' PFR., P. Z. S. 1860, p. 139; 

 Mai. Bl. viii, 1861, p. 80; Monogr. vi, p. 364 (with var. minor} ; 

 Novit. Conch, iii. p. 435, pi. 97, f. 16, 17 (var. minor}. - 

 Eucalodium mexicanum Cum., CROSSE & FISCHER, Journ. de 

 Conchyl. 1868, p. 88; Moll. Mex. i, p. 369, with var. minor 

 and major. STREBEL, Beitrage iv, p. 62, pi. 6, f . 7 ; pi. 11, 

 f. 3 (radula), 11 (jaw), 16 (anat.) ; and var. minor, p. 63, 

 pi. 5, f. 11. 



The original description is given above. The specimens be- 

 fore me are rather thin, flesh-colored under a very thin, 

 pellucid cuticle, which has been lost from most of the speci- 

 mens, but when perfectly preserved gives the shell a gray- 

 brown color, with pink more or less obviously showing through. 

 The sculpture is of irregular, slightly oblique and weakly 

 arcuate growth-wrinkles, the early whorls more regularly 

 though weakly costulate. The base is angular in front, the 

 carina varying in strength and persistence. The last whorl 

 is shortly free, the length of the free portion varying a good 

 deal, and there is also wide variation in the shape of the aper- 

 ture. Peristome white, narrowly reflexed. The colunaella is 

 markedly bent or excavated below. The internal column (pi. 

 7, fig. 12) is a flattened spiral, with the edge more or less 

 roughened by little projections, more widely spaced than in 

 E. compactum. With age the spiral becomes less acute and 

 the projections tend to disappear. 



Length 46, diam. 13y 2 mm. : no. of whorls 8 1 /?,. 



Length 50, diam. 13y 2 mm. ; no. of whorls 9% ; form more 

 tapering. 



Length 49, diam. 13i/ 2 mm. ; no. of whorls 8%. 



The fine sculpture (" sub lente punctulata ") of Pfeiffer's 

 type was obviously due to the condition of the slightly eroded 

 surface. The summit, with its granulose plug and the sig- 

 moid axial pillar, are shown in fig. 17 of pi. 8. 



