, 
386 PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 
The dentition of this species is very different from that of D. robustus 
and D. arborescens. Both of these have the median teeth serrated, and 
different in form; the latter has broader and less acute lateral teeth. 
Off Cape Cod (station 330), 26 fathoms, September 6, 1879. 
Doris complanata Verrill. 
Amer. Journ. Sci., xx, p. 399, Nov., 1880. 
Body depressed, broad-elliptical, well rounded, both in front and be- 
hind, the mantle extending much beyond the foot all around, its edge 
usually undulated. The lower side of the mantle is stiffened with spic- 
ules; upper surface slightly convex, nearly smooth, but covered with 
small, rather distant, and but slightly prominent, conical elevations. 
Dorsal tentacles large, stout, subclavate (not seen in full extension), 
with very numerous, crowded, thin, high, lamelliform plications or folds 
over the entire upper portion; retractile into cavities having plain, sharp 
edges Gills large, the two lower, on each side, partially confluent at 
base, bipinnately and tripinnately divided, retractile into a large com- 
mon cavity, which has plain edges. Anal papilla a prominent, ecylin- 
drical tube in the center of the branchial wreath. Foot relatively small, 
obtusely rounded posteriorly, emarginate in front, and with a transverse 
suicus on the front edge. Head small, rounded in front, with a free, 
short, thick, ovate tentacle on each side. Odontophore broad, with 
about seventy to eighty rows of teeth; no median teeth; about twenty- 
two to twenty-four lateral teeth, on each side, are stout, hook-shaped, 
with sharp points, and a slight lobe on the outer curvature and another 
on the inner side; outside of these there are twelve or more shorter, 
flattened teeth, with obtuse or rounded, incurved, and sharply denticu- 
lated or spinulated ends; the outermost teeth are smallest. Length, 
50°"; breadth, 25™". 
Color, above, dull yellowish brown to dusky brown, irregularly finely 
specked and blotched with dark brown; gills dark brown. 
About 70 miles south of Martha’s Vineyard, station 872, in 85 fathoms, 
among sponges (eleven specimens). 
This large species is closely related to D. Johnstoni and D. planata of 
Europe. It differs from both in its dentition, in having stouter and 
blunter dorsal tentacles, with more numerous lamellwe, and in having 
shorter and blunter oral tentacles. 
Polycerella Verrill, gen. nov. 
Body elongated-ovate, having the same form as Polycera. Mantle 
little developed. Dorsal tentacles (rhinophores) not laminated and not 
retractile, without sheaths. A row of papilla along each side of the 
back, extending beyond the gills. Gills three, pinnate, situated in the 
middle of the back, nearly as in Polycera. Foot auricled. Odontophore 
with six rows of teeth ; median row absent; inner laterals large, curved, 
with three denticles ; two outer rows much smaller, simple, hook-shaped. 
