^1> 

 n 



is slight and obtuse a little above the middle of the last whorl ; spire 

 with the outlines quite convex throughout most of the shell ; apex 

 truncate with the loss of whorls ; ten and one-half whorls re- 

 maining, quite convex, with a deep suture; last whorl slightly pro- 

 duced ; aperture angular at the anterior extremity and on the middle 

 of the right side ; lip thin, sharp, narrow, and moderately reflected. 



Length .315 inch; breadth .1 inch. 



Cyjlindrella Htdeana. Syn. Buliraus Gossei, Pfr. If this 

 species be removed from Buliraus to Cylindrella, it will require a new 

 name. It appears to belong to Dr. Pfeiffer's section 6 of Cylindrella 

 with a persistent apex, and strongly resembles several of the species 

 of that section in its general form, and in the position and form of the 

 aperture. It has the type of sculpture usual in Cylindrella, and like 

 most of this genus, but unlike any species of Bulimus, in Jamacia, it 

 occurs in great profusion among limestone rocks. It is most closely 

 allied to C. pontijica, Gould, Mss. 



C cylindrus, Ad. Proc Bost. Soc. Nat Hist Jan. 1849, received 

 the name of C. rubra in my printed Catologue of shells Jan. 1847. 

 It is perhaps a variety of C. Dunhtri. Pfr., but differs in having the 

 greatest diameter at or above the middle of the shell, while in the lat- 

 ter it is in the lower third, above which the shell tapers regularly, C. 

 rubra is larger, has coarser stz-ice, and is always deep red. C. Dun- 

 keri is always brown. The last loses eight or nine whorls by trunca- 

 tion, and has twelve remaining. 



Cylindrella similis is perhaps another variety of C Dunkeri, 

 Pfr. but is much smaller, has the aperture less angulated anteriorly, 

 angulated at the left end of the upper side, and the lip is much more 

 arched above : the striation is finer in proportion to the size : nine or 

 ten whorls are lost by truncation, and twelve remain. 



Length .475 inch ; breadth .09 inch. 



Cylindrella tenella is much more slender than C. Dunkeri, 

 has thirteen whorls, and the striation is microscopically minute : the 

 aperture is like that of C. Dunkeri, and, like C rubra, it tapers from 

 above the middle down to the anterior extremity. 



Length .5 inch breadth .077 inch. 



Cylindrella tenera also resembles C. Dunkeri in color and C. 

 rubra in form. It is very small, has the aperture orbicular, and the 

 striation microscopic ; it loses six whorls by truncation, and has ten 

 remaining. 



Length .28 inch ; breadth .055 inch. 



