MICROCERAMUS. 165 



Macroceramus infradenticulatus Wr. mss., PFR., Malak. 

 BL, xi, 1864, p. 127; Novit. Conch., p. 405, pi. 93, f. 24-26; 

 Monogr., vi, p. 349. ARANGO, Fauna, p. 83. 



Near M. petitianus, but larger, more strictly conic, and 

 with the small tubercles above the suture more regularly 

 developed. The low keel is marked with white, and the base 

 is radially striped. It differs from M. elegans in little be- 

 sides the larger size. 



11. M. PALENQUENSIS (' Gundl. ' Pfr.). PI. 27, fig. 44. 



Shell imperforate, ovate-conic, thin, very closely, finely 

 striate; irregularly variegated and somewhat banded with 

 whitish and corneous. Spire swollen-conic, the vertex acute, 

 corneous; suture simple. Whorls 8, a little convex, the last 

 rounded. Aperture diagonal, rounded-lunar ; peristome 

 simple, thin, narrowly expanded, the columellar margin 

 somewhat calloused. Length 8, diam. 4.66 mm.; apert. 3.3 

 mm. high. (Pfr.) 



Western Cuba: Palenque de Matanzas (Gundlach). 



Macroceramus palenquensis Gundl. mss., PFR., Malak. BL, 

 1863, xi, p. 18, no. 77 ; Novit. Conch., p. 404, pi. 93, f . 16-18 ; 

 Monogr., vi, p. 349. ARANGO, Fauna, p. 82. 



Distinguished from M. turricula [petitiana], which it re- 

 sembles in stature, by the much finer sculpture, satin luster, 

 smooth suture and comparatively larger aperture (Pfr.). 

 I have not seen specimens. 



12. M. PETITIANUS (Orbigny). PL 27, figs. 50, 42. 



Shell shortly rimate, ovate-acuminate, thin, corneous mar- 

 bled with opaque white ; surface slightly shining, densely and 

 very obliquely sculptured with riblets narrower than their 

 intervals. Spire acutely conic, often with slightly concave 

 outlines above. Whorls 8 to 9, but slightly convex, the last 

 having a very weak, hardly noticeable keel ; the base smoother, 

 corneous. Aperture oblique, rounded, the peristome narrowly 

 expanded and a little thickened; columellar margin but 

 slightly built forward, dilated above. 



Length 7.3, diam. 3.4 mm. 



