A. E. Verrill - — Catalogue of Marine Mollusca. 
505 
The odontophore (fig. 20a). is very slender; the outlines of the 
median plates are indistinct ; they bear three very small but distinct 
and nearly equal denticles; the lateral teeth have only two denticles. 
Length of an ordinary sized specimen, ll mm ; breadth, 5 mm ; length 
of body-whorl, 7‘10 mra ; length of aperture, 5 mm ; its breadth, 2T5 mm . 
The largest specimen (with seven whorls) is 14 mm long; breadth, 
6’5 mra ; length of aperture, 7 mm ; its breadth, 3 mm . 
Off Martha’s Vineyard, in 312 to 506 fathoms (stations 937, 947, 
994, 997, 1029), 1881, fourteen specimens. 
This delicate species is liable to be confounded with the young of 
8. pygnueus, but it differs decidedly in its dentition, operculum, 
nuclear whorls, short and straight canal, and in the character of its 
spiral cinguli. The upper whorls of S. pygmoeus are much more 
angular, with coarser, and more prominent carinse or cinguli, which 
are separated by narrower, incised grooves.* 
This species, by its spiral nucleus, would be referable to the group, 
iS ip ho no rb is, and it also approaches Mohnia Friele, in the character 
of its dentition and operculum. 
Sipho glyptus Verrill, sp. nov. 
Tritonofusus latericeus Verrill, Amer. Journ. Sci., xx, p. 391, Nov., 1880; Proc. U. S. 
Nat. Mus., iii, p. 369, 1880 (non Moll., Morch). 
Plate LVII, figure 22; Plate LVIII, figures 1, la. 
Shell long-fusiform, with a high, tapering, acute spire ; with an im- 
pressed, oblique, undulated suture, with convex, transversely ribbed, 
and spirally grooved whorls; and with a narrow, rather long, nearly 
straight canal. 
Whorls seven to eight, evenly rounded, crossed by about 13 slightly 
curved, regular, rounded, and prominent ribs, separated by rather 
wider, regularly concave interspaces ; the ribs are lower and a little 
excurved just below the suture, and fade out before reaching the base 
* There are two varieties of S. pygmeeus on our coast, which are often well-marked. 
The more northern and larger form has well-rounded whorls, covered with strong 
cinguli and sulci, and with a strongly ciliated epidermis; canal long and much curved. 
The other varioty, which abounds off Martha's Vineyard, etc., in from 20 to .350 fath- 
oms, on muddy bottoms, has the whorls flattened and much smoother; the cinguli 
often obsolete, in part, except on the upper whorls, and the epidermis is darker green 
or olive, and only slightly ciliated, more often nearly or quite smooth, aiftl the canal is, 
perhaps, a little shorter and less curved. This may take the variety name, »*?. pygmoeus, 
var. planultts. The nucleus and apical whorls agree well, however, in the two forms. 
