CYLIXDRELLA. 383 



Cylindrella lactaria, GOULD in T. M., PI. LXIX. Fig. 2, not in text. 

 Gongylostoma Poet/ana, TRYON, Am. Journ. Conch., III. 311 (1868). 



A Cuban species, found also in the Florida Subregion, both on the mainland 

 in the Miami Country, and on Key West and other Keys. 



Animal white, with a dark line along the back of each eye-peduncle, one 

 along the median line, and a very delicate one along each cheek ; ocular points 

 large and black. 



The description in the Terrestrial Mollusks is drawn from C. lactaria, Gould, 

 which is identical with vanegata, Pfeiffer, and is characterized by flexuose, milk- 

 white lines and more delicate strise. 



The apicial nucleus of the shell is a small globule ; this is succeeded by a 

 large number of closely revolving whorls of still smaller diameter, which 

 scarcely augment in length ; and then there is a rapid dilatation to the full 

 size of the shell. At this part, either by fracture, or more probably by ab- 

 sorption, the slender tip is thrown off, so that we have only the truncated lower 

 portion left. 



The animal is very small compared with the shell, being less than one fourth 

 the length of the shell, which it carries with its axis nearly horizontal, and in 

 the line of motion, with apparent difficulty. The snout is thrown forward, and 

 firmly attached at every undulation, simultaneously with the contraction of the 

 posterior extremity. When the curve flowing along the sides of the foot reaches 

 the head, the attachment of the snout is released, and it is again thrown for- 

 ward and fixed as before. 



Jaw as usual in the genus, with about 40 delicate ribs. 



Lingual membrane (PI. X. Fig. R) as described above; teeth 14 1 14. 



Genitalia not examined. 



Cylindrella jejuna, GOULD. 

 Vol. III. PL LXIX. Fig. 3. 



Shell rather small, fusiform, truncated at apex, quite solid, of a pale horn- 

 color, longitudinally striped with delicate, white lines ; spire composed of about 

 9 whorls, though when entire the whole number would be about twice as many ; 

 they are convex, and separated by a well-marked suture ; the last whorl has a 

 delicate carina, and extends in a short neck ; the aperture is bell-shaped, the 

 peristome white, continuous, and not in contact with the preceding whorl. 

 Axis simple. Length, 10 mill.; breadth about 2| mill. 



Cylindrella jejuna, GOULD, Proc. Bost. Soc. Nat. Hist., III. 41, June, 1848 ; Terr. 



Moll., II. 310, PL LXIX. Fig. 3. W. G. BINNEY, T. M., IV. 150 ; L. & Fr.- 



W. Sh., I. 23 (1869). 



Cylindrella variegata, PFEIFFER, part, Mai. Bliitt., II. 13. 

 Gongylostoma jejuna, TRYON, Am. Journ. Conch., III., 312 (1868). 



Found abundantly in the Florida Subregion, near the mouth of the Miami 

 River. 



