1910.] 



NATURAL SCIENCES OF PHILADELPHIA. 



531 



Somerset Road, about two miles from Mandeville. Types No. 

 101,172, A. N. S. P., collected by Dr. A. P. Brown, 1910. 



This species stands between S. tenella and S. elatior (C. B. Ad.). 

 S. tenella is a paler, smaller and more delicate species, with the aperture 

 less or not at all protracted. S. elatior is larger, more finely striate 

 shell, with the axis gyrate in a greater number of whorls. 



Varicella (Varicellula) rapax n. sp. Fig. 12. 



The shell is lanceolate, slender, the length about 3^ times the 

 diameter, thin, corneous, glossy. The outlines of 

 the spire are very slightly convex, nearly straight; 

 apex obtuse. Whorls 6^, moderately convex. The 

 first H whorls are smooth; then narrow vertical 

 impressed lines appear, faint and widely spaced at 

 first, soon becoming deeper, the last four whorls 

 sculptured with nearly regular vertical grooves 

 parted by much wider convex intervals (or wide, 

 very low, convex riblets parted by narrow grooves). 

 On the face of the last whorl there are about 3 such 

 riblets in one millimeter; they are a little more 

 crowded on the last part of the whorl. They extend 

 undiminished to the base. There are also a few very 

 ill-defined slightly deeper varix grooves, two on the 

 last, three on the penultimate whorl. The suture is 

 margined by transparence. The aperture is lanceo- 

 late, quite narrow in the upper third, 40% the length 

 of the shell. The outer lip arches well forward in 

 the middle, retracting above and below. The columella is quite short, 

 vertical, very obliquely truncate at its base. In basal view no "false 

 umbilicus" is visible. Length 10.5, diam. 3, length of aperture 

 4.6 mm. 



Somerset, Manchester. Type No. 101,421, A. N. S. P., collected 

 by Dr. A. P. Brown, 1910. 



This species resembles V. puella (C. B. Ad.) in form of the shell 

 and columella, but differs from it by the very much coarser sculpture. 

 V. tenera (C. B. Ad.) is a much more slender species, which approaches 

 the new form in sculpture. V. rapax certainly differs from all of the 

 numerous Varicellas described by C. B. Adams, the types of which 

 have been redescribed and figured by one of us. Fresher specimens of 

 V. rapax may perhaps show brown streaks along the indistinct varix- 

 grooves. 



Fig. 12. 



