BRACHYPODELLA, JAMAICAN. 103 



Cylindrella alba C. B. AD., Contrib. to Conch., no. 2, p. 20 

 (Oct., 1849). PFR., Monogr., iii, p. 566; Conch. Cab., p. 40, 

 pi. 4, f. 23-25. GLOYNE, Journ. of Conch., 1872, p. 34 (Derry, 

 northern Manchester). JOHNSON and Fox, Nautilus, v, p. 

 34. HENDERSON, Nautilus, viii, p. 20, no. 98 (north of 

 Savanna la Mar). C. subula PFR. in Wiegm. Archiv f. 

 Naturg., 1840, i, p. 41 ; Phil., Abbild., ii, p. 50, pi. 2, f . 13. 

 BINNEY, Ann. N. Y. Acad. Sci., iii, p. 125 (teeth). 



The type locality of B. alba was not stated, and until 

 Adams' type is re-examined, its precise characters will re- 

 main unknown. The type measured 10 mm. long, 2.075 wide, 

 with 13 or 14 whorls remaining. It was thus a short- whorled 

 race, like the varieties eos and minima, but differing from 

 both in being narrower, with more whorls for its length. 



The large series of specimens before me shows rather wide 

 variation, indicating several ill-differentiated races. Indeed, 

 Mr. Jarvis is disposed to segregate the form from the extreme 

 east specifically, as his researches up to this time have shown 

 no connection between the eastern and western herds, which 

 may thus be separated by an area over half as long as the 

 island without species of the alba type. This course seems to 

 me barred by the impossibility of separating eastern specimens 

 from some lots taken in St. Elizabeth Parish, in the west. I 

 have hesitated to attempt the definition of any varieties, but 

 finally decided to do so, merely to stimulate closer study of 

 the group. Their characters are briefly given in the follow- 

 ing key: 



I. Whorls very short, their number greater than the number 

 of mm. in the length of the shell. 



1. Nearly smooth, the striation very faint and fine. 



a. 10 x 2 mm., with 13-14 whorls ; typical alba. 



b. 12.5x2.5 mm., with 13i/ 2 whorls, to 11.2x2.5 

 mm., with 11% whorls. Portland. Var. eos. 



c. 9.5 x 2 to 2.2 mm., whorls 11-12. Var. minima. 



2. Striation comparatively coarse ; 13 x 2.1 mm., with 

 151/2 whorls, to 11 x 2.1 mm., with 13 whorls. West- 

 moreland. Var. striata. 



