A, E. Verrill— Catalogue of Murine Mollusca. 515 
and the submarginal thickening of the outer lip are also good dis- 
tinctive marks, but the great difference in the nucleus is, perhaps, of 
still greater importance. Fresh specimens, when wet, are so.trans- 
parent that the internal form of the columella can often be seen, 
through the shell. 
Astyris pura Verrill, sp. nov. 
This shell is very abundant in many of our deeper dredgings, on 
muddy bottoms. It resembies the shallow-water species, A. zonalis* 
(=A. dissimilis Stimp.), in form, except that it is somewhat shorter 
and stouter, with the whorls more convex, the columella more exca- 
vated, the aperture a little wider and the canal slightly bent back, 
at tip, but the shell is translucent and glossy, and the color is pure 
white, or pinkish white, except near the apex, where it is tinged with 
pale brown or pink, in fresh specimens. The surface is smooth, 
except slight lines of growth and a few faint spiral lines, on the 
eanal, anteriorly. The nucleus is distinctly larger than in the typi- 
eal A. zonalis. It is probable that this form is a distinct species. 
Off Martha’s Vineyard, 100 to 487 fathoms, 1880, 1881,—U. 58. Fish 
Com. ; off Chesapeake Bay, 300 fathoms,—Capt. Tanner. Abundant, 
living, at stations 892, 894, in 487 and 365 fathoms. 
TACNIOGLOSSA. 
Dolium Bairdii Verrill and Smith. 
Dolium Bairdii Verrill and Smith, in Verrill, Amer. Journ. Sci., xxii, p. 296, Oct., 
1881 (description). 
The apical or nuclear whorls are yellowish brown, smooth, showing 
only faint lines of growth, and consist of nearly four turns. The 
color and character of the surface changes abruptly beyond the 
nucleus, the normal sculpture suddenly appearing. The primary 
whorl is very small, regularly spiral, a little prominent. On the 
second whorl below the nucleus there are seven primary darker 
brown ribs, with seven smaller and paler ones, alternating with them, 
and some still smaller ones interpolated. 
The largest’ specimen taken (7) is 68" long; breadth, 56” ; 
length of aperture, 53™", 
Off Martha’s Vineyard, station 945; 202 fathoms, one large living 
(4), stations 1032, 1036, 1038, 1040, 94 fathoms; young speci- 
mens and fragments of several large ones. 

* The true A. zonalis also occurs in this region, from the shore to 100 fathoms. 
The deep-water ones are highly colored and banded, like those from shallow water. 
TRANS. Conn. ACAD., VoL V. 62 JUNE, 1882. 
