1880.] NATURAL SCIENCES OF PHILADELPHIA. 63 



The openings of the rhinophor-holes and of the branchial area (fig. 

 Sbb) surrounded by large and small tubercles which also were spread 

 over the central part of it (fig. 3). The branchial leaves ( fig. 3aa) were 

 about twenty-four or twenty-five in number, set in a transverse reni- 

 form ring ; the leaves in the front part much larger than the rest. 

 The anus as usual, scarcely projecting. The under side of the margin 

 of the mantle quite smooth. The genital openings always quite con- 

 tracted. The foot large, with a fine line along its anterior margin. 



The cerebro-visceral ganglia short-reniform ; the pedal ones not 

 much smaller, of oval form, set nearly at a right angle to the inferior 

 face of the former ; the olfactory ganglia bulbiform or ovoid. The 

 buccal ganglia rather flattened, of roundish contour, a little larger than 

 the olfactory ones ; the commissure between them very short ; the 

 gastro-oisophageal ganglia not very short-stalked, roundish, in size 

 about one-quarter of the buccal ganglia, with three large cells. The 

 three commissures very distinct, the sub-cerebral and the pedal con- 

 nected throughout most of their length ; the visceral thin, not giving 

 off a genital nerve. 



The eyes with black pigment, yellowish lens ; the nervus opticus 

 nearly as long as half the breadth of the cerebral ganglion. The 

 otocysts as large as the eyes, crowded with otokonia of the usual kind. 

 The leaves of the rhinophoria without spicules ; the axis of these organs, 

 on the other hand, were filled with such spicules, partly circularly and 

 concentrically arranged. The tubercles of the back stuffed with ordi- 

 nary spicules (fig. 10) in the usual way, the larger spicules mostly very 

 prominent on the surface 



The oral tube as usual. The bulbus pharyngeus of the usual form, 

 about 2.0 mm. long ; the lip-disk with a rather thick yellowish cuticula, 

 and inwards with the same belt of (about ten to fifteen) rows of small 

 denticles as in the L. hystricina (cf. below) ; the sheath of the radula 

 somewhat bent upwards, freely projecting behind the bulbus for as 

 great a length as that of the bulbus itself. The tongue (in the three 

 individuals) with ten or eleven series of plates, in the sheath ten or 

 eleven developed and tliree younger rows ; the total number of rows being 

 thus twenty four or twenty-five. The plates light j^ellowish in their 

 thicker parts, otherwise nearly colorless. The length of the median 

 plates reaching about 0.12 mm., the height of the external ones 

 0.10 mm. The median (fig. 7a) and exterior plates (fig. Ih) quite as 

 usual ; the large ones of the usual forms (fig. Ih), sometimes, especially 



