136 KFLLETIN OF THJ: BUREAU OF FISHERIES. 



simple or compound tubercles, in some cases approximating the size and complexity of the marginal 

 ones. These are usually irregularly arranged, tending, however, in some individuals to form a median 

 series, especially in the head region (pi. .xxvii, fig. 16). Behind the branchiic a median tubercle, 

 often several scattered ones, and in front of the rhinophores 2 or 3 similar ones. 



Rhinophores retractile into prominent sheaths, the margins of which are thin, smooth, or slightly 

 wavy in outline. Stalk stout, erect; the clavus curved backward and upward, perfoliate with 20-:;i) 

 leaves. 



Branchiic .5, large, tripinnate, wide spreading, entirely separate at the base; 1 antcrinr iiu-dian 

 plume and 2 pairs of lateral ones. In the center of this circle of branchiie is the anal papilla, a 

 conspicuous conical elevation bearing the anal opening at its summit. Near its base on the right 

 side is the minute renal pore. 



Tentacles short and stout, auriform, a longitudinal slit extending along their outer border, the 

 margins of which fold together (pi. xxi, tig. 108, a). In alcoholic material these organs often take on a 

 cuplike form, due to shrinkage. 



Anterior margin of foot rounded, the sides nearly parallel, the posterior end rather abruptly 

 pointed. 



General body color white (pi. xxvii, iigs. 16, 17), inclined to yellowish above, often sprinkled with 

 minute whitespots borne upon very small tubercles. Tipsof branchiae, clavus of rhinophores, appendages 

 of frontal and lateral margins, and the numerous scattered tubercles of the dorsum a deep orange 

 color. Numerous irregular blotches of orange are also scattered along the sides of the animal in 

 no regular arrangement. The region of the body beneath the gill plumes is darker, caused by the 

 deep brown liver shining through the skin. In alcoholic specimens the orange color is lost and the 

 specimens are everywhere white. 



Pharyngeal apparatus large and strong, in shape truncately conical, slightly compressed laterally, 

 the radula sheath projecting below and behind as a rounded eminence. 



Lip disk strongly convex, covered by a strong, brow-nish yellow cuticula, the opening inverted 

 T-shape (pi. xix, fig. 55). Behind the oral slit on each side the cuticula passes into a triangular, 

 brownish yellow plate, broad above, its apex directed downward. In an individual of 5 cm. length 

 this plate has an extreme length of 2 mm. and a height of 3 mm. and is made up of closely set slightly 

 curved blunt rods, those of the anterior border having a length of about 0.150 mm. and a diameter 

 of 0.004 mm. 



Radula broad, deeply grooved, dark amber in color. Teeth in 33 rows, of which 3 are immature 

 at the end of the sheath. Rhachis broad, bearing 4 rows of flattened plates (spurious teeth). The 

 inner 2 rows of these plates, in the older portion of the radula, are quadrangular, about 180// in 

 width by the same in length, grayish yellow, the anterior margin thickened and smooth, the lateral 

 and posterior ones irregular (pi. xix, fig. 51). In the younger, posterior portion of the radula these 

 plates become lighter in color, trapezoidal in shape, and much wider than long (pi. xix, lig. 54); e. g., in 

 the thirtieth row, length of plate 0.150 mm., width of posterior margin 0.240 mm., of anterior margin 

 0.165 mm. The outer row of median plates is made up of more triangular thickenings, the rounded and 

 slightly thickened anterior margin being much narrower than the posterior one, the outer margin 

 prolonged backward, especially in the posterior portion of the radula (fig. 54), where it becomes a 

 long process extending under the pleurte. Pleural teeth yellow, strongly hooked, of nearly uniform 

 shape and size. The number varies in different individuals from 9 to 18. In five different raduUe the 

 number of pleural teeth w-as 13, 18, 10, 9, 14, though for each radula the number is constant in all the 

 rows. The base of each hook bears a wing-like process usually directed at right angles to the direction 

 of the hook, and hence easily overlooked (fig. 53). The uncini (fig. 51), quadrilateral in general 

 outline, vary from 9 to 18 in number in different raduke, while in the same radula the number is not a 

 constant one for all of the rows. A conspicuous longitudinal crest directed toward the median line is 

 borne by most of the uncini. It gradually decreases in size toward the outer portion of the radula 

 and is entirely lacking in the outermost three or four uncini (pi. xix, figs. 51, 52). 



The esophagus is a nearly straight muscular tube passing almost directly backward from the 

 pharyngeal bulb, 10 mm. in length and reaching a diameter of 3 mm. At the anterior border of the 

 visceral mass it dilates into the stomach, which lies in a deep, oblique groove in the anterior end of 

 the liver. The stomach describes a simple loop from right to left, its pyloric portion, emerging from 

 the liver on tlie lower left-hand side, curving upward and forward u])on the upper face of the liver, 



