1 880. J NATURAL SCIENCES OF PHILADELPHIA. 91 



yellow. Very scanty black pigment on the inferior part of the vagina 

 and of the penis ; the peritoneum of the back, on the contrary, very 

 (lark brown. 



2. Acanthodoris pilosa (0. F. MUUer), var. albescens, PL X, fig. 14, 15 ; PI. XI, fig. 2 ; 

 PI. XII, fig. 13-16. 



Color flavescente-albidus. 



Hamus dentium (lingua;) edentulus vel parce denticulatus. 



Habitat. Oceanum Pacificum septentrion. (Aleutian Islands). 



Two rather large specimens of this variety have been dredged by 

 Dall, in June and July, 1813, at Kyska Harbor (Aleutians), on sand 

 or on rocky bottom, at a depth of nine to fourteen fathoms. 



According to Dall, the color of the living animal was "yellowish- 

 white ; " that of the specimens preserved in spirits was so, too, but 

 very likely much more whitish. The length was 16.0 or 17.0 mm., 

 by a breadth of 6.5 to 8.0 mm., and a height of 6.5 mm. ; the h^^ight 

 of the rhinophoria 2.5 to 3.0 mm., of the gill 3.0 to 4.0 mm. ; the 

 breadth of the foot 5 or 6.0 mm., the length of the genital opening 

 2.0 or 3.0 mm. The form as in the typical D. jnlosa; the rhinophoria 

 showed about twenty-five broad leaves in the club ; there were nine 

 branchial leaves ; the anal papilla very low ; the renal pore rather large. 



The central nervous system as previously described. The distal 

 olfactory ganglion small ; a large (diameter, 0.4 mm.) ganglion penis 

 (fig. 15). The eyes with rich, coal-black pigment ; the otocysts visible 

 under a lens as chalk-white points, with about one hundred and fifty 

 otokonia. 



The bulbus pharyngeus 8.5 mm. long, with the sheath of the radula 

 projecting 1.3 to 1.5 mm.; the height of the bulbus, with the crop, 

 4.0 to 4.5 mm., its breadth 2.5 to 3.0 mm. 



The older elements of the lip-plate (PI. XII, figs. 13, 14) agreeing 

 in form with those of the typical species, but oftener showing a granu- 

 lated interior ; the said elements reaching a length of about 0.04 mm. 

 The diameter of the disk and mouth about 3.0 mm. The breadth of 

 either half of the disk 0.66 mm. 



The tongue showed nine or ten rows of teeth ; the whole number of 

 rows, twenty-nine (16 or 174-3). The large lateral teeth were as in the 

 typical species, reaching 0.65 mm. in height (PI. XII, fig. 15, 16), 

 without or with only a very slight denticulation of the hook (fig. 15). 

 The number of the outer teeth, three to five.' 



' Cf. my Gatt. nordischer Doriden, 1. c, Taf. xix, fig. 13. 



