1880.] NATURAL SCIENCES OP PHILADELPHIA. 109 



foot 2.0 mm. The color of the animal whitish, that of the rhinophoria 

 and the branchial leaves more yellow ; the margin of the foot white. 



'The form as usual. The head rounded, with a prominence on the 

 upper lateral part ; the mouth a vertical slit. The margin of the 

 rhinophor-grooves plain. The stalk of the rhinophoria nearly as high 

 as the club, cylindrical ; the club rather flattened, with about fifteen 

 leaves; before the rhinophoria a low transverse frontal veil with 

 scarcely more than two prominences ; the veil continued backwards as 

 a rather indistinct prominent line on each side of the smooth rounded 

 back ; the pericardial region a little prominent ; behind the middle of 

 the length of the back, the gill with six tripinnate leaves in a slight 

 curve ; behind them the quite low anal nipple, and towards the right 

 side the renal pore ; behind the gill a little flattened space with a slight 

 crest on each side with three papilliB. The sides of the body rather 

 high. In the region of the anterior angles of the foot the genital 

 papilla with the everted penis (without its recurved point, 0.75 mm. 

 high), and below it a folded lamella, the duct of the mucous gland. The 

 foot rather narrow, of nearly the same breadth ; the rounded anterior 

 angles somewhat prominent ; a fine furrow in the anterior margin. 



The intestines indistinctly appearing through the walls of the body. 

 The peritoneum colorless, nearly without spicula. 



The central nervous system (fig. 1) very depressed; the cerebral 

 ganglia of rounded-triangular form, a little larger than the more 

 rounded visceral (fig. la); the pedal ones more pyriforra, a little 

 larger than the last ; the (proximal) olfactory ganglia bulbifonn, not 

 quite as large as the buccal ones, which were (fig. lb) of rounded form, 

 connected by a not very short commissure ; the gastro-oesophageal 

 ganglia of about one-eighth of the size of the former, rounded.^ The 

 three inferior ( subcerebral, visceral, and pedal) commissures (or at 

 least the visceral one) free. 



The eyes (fig. 1) short-stalked, with black pigment and pale yellowish 

 lens. The otocysts (fig. 1 ) in their usual place, very short-stalked, 

 with about eighty otokonia of the ordinary kind. In the stalk of the 

 rhinophoria some scattered yellowish thick spicula, of the same kind 

 as in the skin of the back ; none, on the contrary, in the leaves of the 

 club. In the skin some scattered, yellowish, thick, straight or curved 

 spicula, mostly of about 0.15-0.3 mm. in length, and of the usual 

 form. In the interstitial tissue very few larger spicula. 



^ In the other species of Polycera I have examined, I never saw gastro- 

 CBSophageal ganglia, nor any in Ewplocamui or iu Plocamopherus . 



