386 PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 



The dentition of this species is very different from that of D. rohustus 

 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), 20 fathoms, September G, 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 

 €dges Gills large, the two lower, on each side, partially conlluent at 

 base, bipinnatsly and tripinnately divided, retractile into a large com- 

 mon cavity, which has j)lain edges. Anal papilla a i)rominent, cylin- 

 drical tube in the center of the branchial wreath. Foot relatively small, 

 obtusely rounded posteriorly, emargiuate in fi-ont, and with a transverse 

 sulcus on the frout edge. Head small, rounded in front, with a free, 

 short, thick, ovate tentacle on each side. Odontophore broad, Avith 

 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 

 Oil 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 fiithoms, 

 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 lamelhie, and in having 

 shorter and blunter oral tentacles. 



Polycerella Verrill, gen. uov. 



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 papillae 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. 



