1879.] NATURAL SCIENCES OF PHILADELPHIA. 99 



remarking that they are found larger than the figure he gives, 

 which has a length of seven to eight centimetres. 



Of this curious form only one specimen was found by Dall at 

 Unalashka, on a reef at low water (in April, 1872). The color of 

 the living animal is noted as having been " ashy gray." 



The color of the animal, preserved in spirits, was uniformly 

 light gray-yellowish; on the pinnae of the plumes of the rhino- 

 phoria, but especially on the envelope of the papillae of the club 

 of these, were remains of a silverish-white, which is also seen on 

 the lobes of the anus and the renal orifice. The length of the 

 bod} r was about 75.0 by a breadth of 37.5, and a height of 26.0 mm. 

 In general the form of the animal was somewhat as in the typical 

 Tritonia, rather stout ; the anterior part of the body hardly nar- 

 rower than the median, the posterior somewhat constricted. The 

 back was a little convex, sloping backwards, rather smooth or 

 very minutely granulated, feeling a little rough to the touch ; on 

 the edge finely tuberculated. 1 The edge projecting about 6 mm.; 

 thinner towards the border, which is finely and irregularly toothed, 

 but showed (PI. III. fig. 14) few traces of gills; 2 on the left side 

 the margin is continued to the (left) rhinophorium, on the right 

 it did not reach quite to the region of the genital openings; back- 

 wards it grew narrower and thinner, over the tail it was nearly 2 

 mm. broad. The rhinophoria are rather distant from each other, 

 almost entirely as in the Tr. Hombergi ; the apertures of the pro- 

 minent sheaths oval, with a diameter of about 6 mm., with the 

 border undulated, and involuted. The stalk of the club low ; the 

 club itself cylindrical, about 3.75-4.0 mm. high ; the central part of 

 the club much lower, oblique; in the periphery the club is divided 

 in several (about ten) larger, commonly bi- or tripinnate plumes, 

 which sometimes are again divided into a medial with a lateral 

 one on each side ; between these stand sometimes one or two 

 smaller and single plumes ; the foremost is the lowest ; the hind- 

 most of all the plumes is the largest, and the stem of this is 

 produced in a thick papilla projecting over all the plumes; from 



1 Pallas mentions the back as more unequal (" grandinoso-inrequalre"). 



2 Very likely the gills were rubbed off; on the other hand, Pallas, too, 

 does neither mention nor in his figure represent gills, he only says that 

 the back side has "anguli carunculato hiulci." (The animal when fresh 

 showed no traces of any gills to the casual observer, and had not been 

 subjected to rough handling. Dall.) 



