94 PROCEEDINGS OF THE ACADEMY OF [1880. 



a breadth of 2.0 and a height of about 3.0 mm. ; the sheath of the 

 radula projecting backward nearly 1.0 mm. ; the lip-disk sometimes 

 surrounded by a ring of black pigment. The armature of the lip- 

 disk entirely as shown (PI. XII, figs. 1-4, 10-11) by me in the form 

 from the Pacific, also the crop (PI. XIII, fig. 2) of the bulbus.' 

 The tongue in the eight specimens examined was provided with five, 

 seven, eight, nine rows of plates, farther backwards also sixteen to 

 twenty developed, and three younger rows; the total number amount- 

 ing thus to from twenty-seven to thirty.^ The large latei-al teeth^ yellow 

 in the body, especially in the anterior-inferior part, with commonly five 

 to eight denticles on the inside of the hook ; sometimes, especially in 

 the younger plates, the number of denticles rose from eleven to fifteen, 

 sometimes the three to four outermost denticles were much larger than 

 the rest, sometimes the denticulation was quite irregular ; the height 

 of this plate reached 0.4 mm. The outer plates (PI. XI, fig. 1) com- 

 monly four to six, seldom seven to eight ; in a series of four on the 

 hinder part of the tongue, the outermost measured about 0.05, the next 

 0.09, 0.11, 0.125 mm.; they were quite colorless, compressed, with 

 the upper side flattened, and rather erect. 



The salivary glands as in the purple-colored form from the Pacific. 

 No constant dilatation of the middle of the oesophagus (as figured, 

 PI. I, f. 12^', by Alder and Hancock), but a strong, particular one at 

 the root as figured (1. c. PI. I, f. 12/j by Alder and Hancock and by 

 me (Gatt. nordischer Doriden, 1. c. Taf. XIX, fig. 14r). The 

 stomach as in the Pacific form ; the intestine sometimes dilated in its 

 first part, sometimes absolutely of the same caliber as the rest, and 

 neither externally nor internally different from it ; a little bag 

 (biliary sac) which has been noticed by Alder and Hancock (1. c. PI, 

 I, fig. 12^'), opening into the right side of this part of the intestine. 

 The posterior visceral mass (liver) flattened and excavated on the 

 anterior-inferior right half. The sanguineous gland whitish, convexo- 

 concave, short and irregularly kidney-formed, with the excavation 



^ The first specimens of the Nortliern Atlantic left at my disposition 

 being too small and too few for a thorough examination, I am obliged to 

 refer to my examination given herewith of the form fiom the Pacific. Cf. 

 moreover my figures iu "Gatt. uord. Doriden," 1. c. PI. XIX, figs. 10, 11. 

 The crop is rather well figured by Alder and Hanc. (1. c. PI. I, f, 12c). 



* According to Meyer and Moebius, the number of plates ("of the 

 radula") is thirty-one, to Alder and Hancock, twenty-seven. 



* Cf. my Gattungeu nordischer Doriden, 1 c. Taf. XIX, fig. 12. 



