A. E. Verrlll — JJollusea of the Nevi Enghind (Joasf. 147 



subsutural band. The animal is destitute of an operculum, and, in 

 all the species hitherto examined, is without eyes. The dentition 

 consists of rather strong uncini, usually with a barbed tip and broad 

 base. 



This genus, therefore, resembles very closely the shallow-water 

 genus, Defraxcia, to which many of the described species have been 

 hitherto referred ; but in Defrancia the outer lip is thickened, or has 

 a distinct varix, and there is usually a deposit of callus on the body- 

 whorl, especially jjosteriorly, opposite the sinus, while the animal, in 

 the typical species at least, has well developed eyes. 



Pleurotomella Bairdii Venill and Smitli, sp. nov. 

 Plate XXXI, figure 1. 



Shell large, rather stout, fusiform, with an elevated, acute, turreted 

 spire and eight or nine obtusely shouldered, angular whorls. The 

 last whorl is large and somewhat inflated, with a broad, flattened or 

 slightly concave, sloping subsutural band, which is covered with dis- 

 tinct, strongly receding lines of growth and with more or less evident, 

 raised, spiral cinguli and grooves. Below the subsutural band the 

 whorls are obtusely aiigulated, but without a distinct carina. Com- 

 mencing at the shoulder and extending a short distance below it are 

 numerous oblique, not very elevated, longitudinal ribs, which fade 

 out before reaching the middle of the whorls. The whole surface of 

 the whorls, including the ribs, is covei'ed with conspicuous, raised, 

 spiral cinguli, between which there are two or three smaller ones, sepa- 

 rated by deep concave grooves of about the same breadth ; the w^hole 

 surface is covered by distinct, raised lines of growth. The aperture 

 is oblong-ovate, rather large ; the columella is nearly straight, some- 

 what prolonged, its inner edge forming a slight sigmoid curve; the 

 canal is short, broad, narrowed at the tip and not recurved ; the outer 

 lip is sharp and thin ; the posterior sinus is broad and rather deep, 

 with regularly rounded margins, corresponding to the lines on the 

 sub-sutural band; below the shoulder the lip projects considerably 

 forward and then is somewhat flattened and recedes gradually to the 

 base of the short and broad canal. The nxiclear whorls are very 

 small and generally eroded so far as to appear smooth. 



The shell is white or grayish white, without any distinct epidermis ; 

 aperture clear white. The animal is destitute of operculum and eyes. 



In the number of specimens examined there is considerable varia- 

 tion in the ratio of length and breadth, depending largely on the 



Trans. Conn. Acad., Vol. VT. 19 April 12. 1884. 



