4 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 70 



which is indistinct, extending from the vicinity of the eye to about 

 25 mm. above the flipper, and then running in a straight line to a 

 point midway between the anus and the lateral base of the flukes. 

 The hide appears glossy when wet and dull when dry, and is very 

 thin and probably pliable, although naturally it is hardened by the 

 action of the preservative. 



General form. — Reference to Figure 1 (drawn with the aid of a 

 Wollaston prism and then corrected for symmetry) will give a better 

 idea of the general form than can a printed description. The bulge 

 of the forehead lends an appearance of anterior heaviness to the 

 body, and there is no depression in the vicinity of the neck, although 

 such may be present in the preserved animal, due to a cramped 

 position after death. 



Head. — The lips are rounded and horny, and the whole anterior 

 part of the head, save posterior to the corners of the mouth and at 

 the apex of the frontal prominence, is tough and elastic to the touch, 

 something like a well-inflated pneumatic tire. Even the corners of 

 the mouth are sufficiently hard to cause one to wonder how free move- 

 ment of the lower jaw is possible, as of course must be the case. 

 There is a slight depression which appears posterior to the chin when 

 the mouth is open. 



The eye is very small, the distance between the canthi of an im- 

 mature measuring but 12 mm., and the eyeball is set flush with the 

 surface of the cheek. The eyes are open in the preserved specimens, 

 and yet the upper and lower lids are unwrinkled, as it seems they 

 should be were they fully functional. In addition, the tissue about 

 the eye is so fibrous that it is obvious that the mobility of this region 

 is impaired to an indeterminate extent. 



The subdermal portion of the external auditory tube is indicated 

 by a slight depression or dimple in the integument, which in the last 

 animal dissected was 111 mm. posterior to the angle of the mouth, a 

 line extending between these two points running just below the eye. 

 The external opening is minute, but the auditory tube broadens sub- 

 dermally and is curved as indicated in Figure 11. 



The apex of the frontal prominence yields more readily to manual 

 pressure than do other portions of the head because of the presence 

 beneath this spot of a deposit of soft fat. The blowhole is situated 

 a trifle caudad of a line running directly vertical through the eye. 

 It is 22 mm. in transverse measurement and slightly crescentric, the 

 concave aspect facing craniad. The edges are lightly rounded. 



Anterior linib. — The flipper or anterior limb varies considerably 

 in relative size. Thus in the adult female the right flipper was 16 

 per cent of the total length, in one of the immatures dissected, 14 per 

 cent; and in the other immature investigated and the Wulsin 



