138 BULLETIN OF THE BUREAU OF FISHERIES. 



its distal end branches into several blunt or knoblike divisions, which may in turn be branched or knf>l i- 

 bed (pi. XKViu, fig. 18). This frontal margin extends laterally below the rhinophores and in it;^ 

 prolongation along the dorso-lateral margin is a series of 4 to 6 short, branched processes essential I \ 

 similar to those of the frontal margin. Posterior portion of the body sloping rapidly downward frcjin 

 a point just in front of the branchiw into the short, blunt tail, which is highly arched above. 



Rhinophores stout, club-shaped, rising from a conical base and expanding above info a broaili i 

 clavus, directed backward and in turn tapering to a blunt tip. Length of clavus the same as that 

 the stalk, or nearly so, about 3 mm. Clavus perfoliate with about 18 plates, which are habitu:ill 

 carried in a nearly vertical position. Rhinophores retractile into conical sheaths about one-third tin 

 height of the whole rhinophore. Margin of sheath smooth or slightly crenulate, fluted longitudinally. 



Below tbe broad semilunar frontal margin (pi. xxi, fig. 106) the rounded, full-lipped mouth, 

 sucker-like in general appearance, at each side continuous with the oral tentacles. Oral tentacles 

 auriform, directed forward and outward, the base cylindrical, outer half deeply grooved on upper 

 side and transformed into a rolled plate, truncate at top with a wavy, sinuous margin (pi. xxi, fig. 

 107). (ireatest diameter of tentacles equal to one-half their total length. 



Branch i;c on po.sterior dorsum arranged in a circle about the anus in 5 tripiunate divisions arising 

 from separate bases. Anterior plume unpaired in median line, the remaining 4 paired and laterally 

 placed. Plumes low, wide spreading, nonretractile. 



Anal opening at summit of conspicuous cylindrical papilla in the center of the circle of branchia>. 



Renal opening an inconspicuous slit on the base of the anal papilla on its right anterior side. 



Color of dorsum and sides yellowish brown, usually of very deep shade, but in some individuals 

 quite light. Dorsum and sides of body everywhere thickly set with small bluish-white round or oval 

 spots, each one forming the center of a very slight polygonal eminence bounded by narrow orange- 

 yellow lines upon the dark-brown background (pl.xxvin. fig. 18). Foot below orange yellow with fine 

 dark-brown flecks save at the margins, which are clivitili'ip onuiL'i'. sliadiii'j off aliuve on the sides into 

 the deep yellowish brown of the dorsum. In smalli-r iiiiliviiliuil> the i;ciii-ial lol.irs are usually lighter, 

 tending to a light orange, the lighter bluish-white spots liring suiullcr au'l less conspicuous. Frontal 

 and doiso-lateral processes and tips of branchial plumes bright orange or vermilion, shading below 

 into dark brown. Stalk of rhinophore yellowish, leaves and antero-median line of clavus and margin 

 of the sheath edged with bright orange red. , 



Pharyngeal bulb very large and strong, conical, slightly compressed laterally, the radula sheath 

 projecting behind and below as a rounded eminence. Length 4 mm., width 2.5 mm., height 2 mm. 

 in an individual of 15 nun. total length. 



Labial disk oblique, oval, somewhat convex, the opening of an inverted T or Y shape (pi. xix, fig. 

 59). Cuticula not thick, colorless, prolonged inward to form the tubular mouth lining, its sides con- 

 tinuous with the dark yellow, triangular mandibular plates characteristic of the genus. These plates 

 are broadest above, the apex directed ventrally, and the anterior and dorsal margins are of nearly 

 equal length, forming a right angle at their junction.. The plates are made up of short, flexible, blunt, 

 cross-striated rodlets having a diameter of about 3 //. 



Radula broad and short, deeply grooved, light yellow in color, and made up of about 14 rows of 

 teeth. Rhachis broad, bearing 4 .series of flattened plates (spurious teeth). The 2 innermost rows 

 are quadrangular in shape, colorless, the anterior margin thickened and fairly smooth, the posterior 

 one jagged and irregular (pi. xix, fig. 57, a). These jjlates increase in length from the anterior (older) 

 end of the radula backward, and also, though less, in width, the general quadrangular shape remain- 

 ing the same. The outer rows of rhachidian plates are made up of flattened triangular elements, 

 slightly larger toward the sheath than in front. They are about as long as broad and bear a more or 

 less extensive thickening in the central region, the lower inner corner of which is occasionally ])ro- 

 longed into a sli.rht cusp (|il. xix, fig. 57, h). Pleural teeth 4 in older portions of the radula, usually 5 

 toward thr sliratli, latL'i', stron'j:ly hooked, of nearly the same size and shape, the abaft with a wing- 

 lik,- ,.x|,aiision ,,„ III,. ,lo,sal si^l.Mpl. xix, fig. 55, o,"58). Uncini (pi. xix, figs. 56) 7 to 8 in number, 

 the fii-^t . .iH-s slightly prismatic in form, gradually becoming reduced to elongated flattened plates. The 

 first 4 or 6 of nearly the same size, then decreasing rapidly to the outermost ones. A well-developed 

 longitudinal crest, directed toward the median line and slightly overlapping the adjacent tooth, is 

 borne by all except the outermost 2 or 3 uncini. 



