1899.] 



NATURAL SCIENCES OF PHILADELPHIA. 



473 



A NEW SPECIES OF THERSITES. 



BY HENRY A. PILSBRY. 



Thersites Webbi, n. sp. Figs, l, 2 



Shell obliquely umbilieate, dome-shaiDed above, moderately con- 

 vex below the carinated periphery; sti-ong and solid. White under 



a dense olive brown cu- 

 ticle above, with some 

 yellowish streaks, be- 

 coming dirty flesh- 

 tinted on the earlier 

 four whorls, which are 

 partially denuded of the 

 thin cuticle ; the base 

 darker, chestnut col- 

 ored, being dull red un- 

 der the cuticle. Sur- 

 face rather glossy, more 

 so beneath, showing 

 moderate, irregular 

 growth - wrinkles ; the 

 upper surface of the 

 last whorl sculptured 

 with oblique, forwardly 

 descending fine wrin- 

 kles, very low and in- 

 conspicuous. Spire 

 dome-shaped, the apex 

 obtuse. Whorls 6|-, 

 slowly widening, those 

 of the spire flat, the 

 suture not impressed ; 

 ^^^- 2- the last whorl strongly 



carinated at the periphery, the keel blunted behind the lip, 

 slightly swollen below the suture, abruptly and deeply deflexed in 



