140 BULLETIN OP^ THE BUREAU OF FISHERIES. 



Mead flattened above, vvitli a conspicuous semicircular frontal margin bearing 8 to 12 tuberculate or 

 branched processes (pi. xxviii, fig. 19). Frontal margin extending laterally well beyond the region of 

 the rhinophores. Dorsum arched, smooth, of a yellowish-brown color, flecked everywhere with bluisli 

 ?pota or entirely plain, the processes of frontal margin and dorso-lateral region, the tips of the 

 branchiic, and tip of the tail yellowish red. Dorso-lateral margin marked out by a series of 4 to li 

 1)rancliing processes similar to those of the frontal margin but longer, reaching a length of 10 luiii., 

 the Ijranchings quite short. 



Foot linear, rounded in front, more grailually tapering behind to the liluntly pointed tail. 



Mouth directed obliquely downward, the tentacles^Jilunt, auriform, 3 mm. long, the outer lialf in 

 the form of a rolled plate, the opening \ipward. 



Rhinophores fairly large, perfoliate with about 20 leaves, the stalk stout, conical, the clavus 

 conical, inclined backward, completely retractile within con.spicuous cylindrical sheaths with smooth 

 margins. 



Branchie 5 in number, tri- and quadripinnate, wide spreading, their bases separate, arranged in a 

 circle around the anus. Anal opening at the top of a large cylindro-conical papilla, the renal opening 

 slit-like, situated on the base of the anal papilla at the right anterior side. 



Pharyngeal bulb large, slightly conical, not depressed nor compressed, the radula sheath project- 

 ing from the ventro-posterior surface as a rounded enlargement. Salivary glands long, band-like, 2 

 mm. broad, extending back under the liver for about 10 mm., the distal ends connected in a loop. 



Labial disk oval, but slightly convex, the opening vertical, an irregularly inverted Y-shape below, 

 on either side below the mandibles a deep fold. Within the opening the colorless cuticula passes over 

 above, laterally, into the light-yellow mandibles, which are elongate triangular in shape, much 

 reduced in size as compared with other species of this genus, occupying less than the upper half of 

 the sides of the flattened oral tube. The mandibular plates are about twice as long as broad, and are 

 made up of short, slender, slightly-curved, elastic, blunt rods from 2 to (5 /^ in diameter, the longest 

 at dorso-anterior margin and decreasing in length behind and below. 



Radula large, broad, straight, deeply grooved, the deep amber teeth in 18 rows, of which the last 

 2 are immature. 



Rhachis broad, with 4 series of flattened plates (spurious teeth). The 2 median rows (pi. xi.x, 

 fig. 60, o) of nearly equilateral rectangular form throughout the wliole radula, their length and width 

 being about 0.270 mm. About one-fourth the length of the plate behind its anterior margin it is 

 thickened into a sharply defined transverse cutting ridge of a light-yellow color, contrasting strongly 

 with the grayish remaining portion of the plate. About one-third the length of this ridge, from the 

 inner margin of the plate, a fainter longitudinal ridge, sloping toward the anterior margin, joins it 

 (PI. .XI.X, fig. 60, a), and in the posterior portion of the radula a similarly placed ridge toward the outer 

 side of the radula may mark off with it a rectangular elevated area (pi. xix, fig. 61). Margins of the 

 plate irregular, especially the posterior one. In the posterior portion of the radula the region of the 

 plate behind the transverse ridge tends to become convexly thickened in its inner median area (fig. 61 ). 

 The plates of the outer series (pi. xix, fig. 60, 6) of the rhachis are triangular in general shape and of a 

 light-yellow color. The anterior inner angle is sharp and thickened, the other two rounded and 

 thinner. The antero-latei'al border is thickened and slopes upward into a strong, rounded, longitu- 

 dinal elevation, which terminates posteriorly in a heavy, blunt cusp, its apex forming a shoulder on 

 the antero-lateral border just below the anterior angle of the tooth. 



Pleural ( pi. xix, fig. 62) with 8 strong, large, amber-yellow teeth of similar form, strongly hooked, 

 decreasing in size but little from within outward. In the anterior region of the radula the number 

 may be reduced to 7. The body of each tooth is long, obliquely placed, slightly curved, and t,visted 

 at its lower end toward the median line of the radula. The hook is large, directed slightly inward, 

 and flattened dorso-ventrally with a broadly pointed cutting edge. A small, inwardly directed wing- 

 like expansion is borne on the basal portion of the shaft. 



Uncini (pi. xix, fig. 63) prismatic, amber colored, 8 in number, the shai)e of the first ones much 

 resembling the bodies of the pleurfe with occasional indications of a hook above. The inner 4 of nearly 

 the same size, their length aljout 300 mm., width about 70 mm., the outer 4 becoming flattened and 

 decreasing rapidly in size, the outermost one being colorless and almost rudimentary. A longitudinal 

 wing-like crest projects toward the median line, often overlapping the adjacent tooth, as in the other 

 species of this genus. 



