162 MICROCERAMUS. 



17 (1864) ; Monogr., vi, p. 351. ARANGO, Fauna, p. 84. 

 M. guanensis C. & F., Miss. Sclent. Mex., Moll., i, p. 425. 



Very much like M. turricula in shape, but readily known 

 by its strongly toothed suture. The keel mentioned by 

 Pfeiffer is often so low as to be readily overlooked, and it 

 does not extend to the smooth, rounded front of the whorl. 

 As usual in this group of species, the earlier post-nepionic 

 whorls are very convex, almost angular. The size varies 

 within wide limits, topotypes measuring 8.2 x 3.5 mm. with 

 9% whorls ; 5.6 x 2.6 mm. with 8% whorls, and 6 x 2.5 mm., 

 8% whorls. 



The name was changed by Crosse & Fischer on account 

 of the earlier Cyl. denticulata, which seems, however, to be 

 referable to Urocoptis. In the Monographia, vi, Pfeiffer mis- 

 quotes both the name and volume in his reference line. Fig- 

 ured from topotypes collected by Wright. 



9. M. SWIFTI (Bland). PL 26, figs. 13, 14, 15. 



Shell very shortly rimate, cylindric turrited; white, copi- 

 ously sprinkled with corneous-brown dots, and more or less 

 streaked with the same tint, the upper whorls mainly brown. 

 Sculpture of very fine, close, low striae throughout. Whorls 

 10 to ll 1 /^ moderately convex, the last rounded below, with 

 an obsolete carina or none. Suture smooth, not crenulate. 

 Aperture round, brown within ; peristome white, very slightly 

 expanded, the columellar margin dilated. 



Length 11, diam. including lip 4 mm. (Eland's type). 



Length 10, diam. above aperture 3.3 mm. 



Bahamas: Turk's Island (type loc. ; Geo. Gibbs, 1866, in 

 Swift coll.) ; Inagua (Bid.). 



Macroceramus swifti BLD., Ann. Lye. N. H. of New York, 

 xi, p. 83 (1874). PFR., Monogr., viii, p. 420. 



As in allied species, the apex is costulate. It differs from 

 M. gossei and its allies by the even, not papillose suture, 

 which at most may be a little irregular in rare specimens, 

 and by the coloration of brown dots and streaks on a pink- 

 white ground. In some specimens a corneous-gray shade re- 

 places the warm brown of the markings, and the spire then 

 is white. 



