A. E. Yen' ill — Catalogue of Marine Mollusca. 
45 
Ct a s t ropo d a . 
TOXOGLOSSA. 
Pleurotoma Dalli Yerrill aud Smith, sp. nov. 
Plate LVII, figures 1, la. 
A slender, transversely ribbed species, remarkable for the deep 
notch, widest within, and the deeply concave subsutural band. 
Whorls ten, somewhat angular and shouldered; nucleus smooth, 
rather large, subglobular, of about one and a half whorls, as broad as 
the next whorl, the first nuclear half- whorl is nearly covered by the 
next, the surface is glossy, marked on the lower half-whorl with rather 
indistinct spiral lines, which become more distinct on the next whorl. 
All the remaining whorls, except sometimes the last, are crossed by 
strongly marked, somewhat obilque, angular ribs, which are most 
elevated at the shoulder, below the strongly marked, concave, sub- 
sutural band ; they do not extend on this baud, and mostly fade out 
below, before reaching the suture; on the body-whorl the ribs are 
less distinct and sometimes absent, when present they extend only a 
little below the suture. The whole surface is covered with fine, wavy, 
spiral lines ; fine, but rather conspicuous, lines of growth cover the 
surface, aud recede strongly on the subsutural band. 
Aperture small, ovate, rather narrow. Outer lip with a prominent, 
convex edge, which has a deep notch, situated a short distance below 
the suture. The notch is usually constricted or even nearly closed 
up at the edge of the lip, but is broadly rounded at its inner end ; 
this gives it a button-hole like appearance. In some specimens it is 
but little constricted. Canal short, broad, slightly everted. 
Color, brown of various tints; often deep brown, with one or two 
spiral bands of yellowish brown, and with streaks of light brown; or 
the ribs may be pale yellowish brown; aperture brown within; colu- 
mella whitish in front. Animal not seen. Operculum not observed. 
Length of the largest specimen, 19-5 rnm ; greatest diameter, 6' 1 " 1 ' ; 
length of body-whorl and canal, 10"""; of aperture, G mm ; breadth of 
aperture, 2'5 mm . 
Off Martha’s Vineyard, stations 1035, 1036, 1038, 1039, in 94 to 
14G fathoms, 1881. Off Delaware Hay, station 1040, 104 fathoms, 
dredged by Lieut. /. 1.. Tanner, Oct. 10, 1881. 
This very curious and handsome species we have dedicated to 
Capt. W. II. Dali, of the U. 8. Coast Survey, who has done much for 
American malacology. 
Trans. Conn. Acad., Vol. V. 
54 
April, 1882. 
