1879.] NATURAL SCIENCES OF PHILADELPHIA. 113 



The central nervous S3^stera as usual, hut less depressed, and of 

 greenish color; the cerebro-visceral ganglia reniform, somewhat 

 broader in front; the distinction between the cerebral and the 

 visceral parts very pronounced, the latter a little smaller than the 

 former; the pedal ganglia rounded, a little larger than the visceral. 

 The buccal ganglia larger than the (proximal) olfactory, roundish, 

 connected by a rather short commissure; the gastro-oesophageal 

 roundish, having about one-tenth of the size of the former, rather 

 short-stalked, developed on one side of the nerve, with one very 

 large and a few smaller cells. The proximal olfactory ganglia 

 rather depressed bulhiform ; the distal ones much smaller, of oval 

 form. 



The lens of the eye was greenish-blue, the pigment brownish- 

 black; the retina bluish. The otocysts were as usual. There 

 were no spiculae in the skin, the leaves of the rhinophoria or the 

 interstitial tissue, which was always of a greenish-blue color. 

 The nodules of the caudal veil resembled those of other species 

 possessing them. 



The oral tube was about 2.5 mm. long, and 1.6 mm. in diameter 

 at the posterior end ; of greenish-blue color throughout. The 

 bulbus pharyngeus of the same or a darker shade, about 3.0 mm. 

 long, by a breadth of 2.5 mm , and a height of nearly 2.0 mm. 



The large sheath of the radnla prominent posteriorly is also 

 about 1.0 mm. in diameter. The lip-plates are of a grayish olive- 

 green color, separated at their upper (fig. 6) and more widely at 

 their lower ends. The plates are scarcely narrower above, the 

 nearly uniform breadth being 1.5 mm. The elements of the plates 

 reach the length of 0.045 mm., with thick, recurved, hooked points 

 (figs. 7-10), these last were seldom cleft (fig. 10). The elements 

 adjacent to the spaces between the plates were much smaller and 

 of irregular form (fig. 0). The tongue was of the usual form, the 

 radula shining like silver and grayish-green in color. In the 

 radula were thirty-five rows of plates, behind which were fifty-one 

 well-formed and six immature rows ; the total amounting to eighty- 

 two rows. In the posterior rows of the tongue were ninety-eight 

 teeth on each side of the narrow and naked rhachis. The teeth 

 had a very pronounced greenish hue ; rising to the height of about 

 0.1 mm., that of the outermost was about 0.04 to 0.06 mm. The 

 form as usual; the hook bifurcated at the point, the outer and 

 posterior branch shorter, denticulated (figs. 11-13), and the den- 



