150 BULLETIN OF THK lUTRKAU OF FISHERIES. 



Iiortioiis of ilorsiiin and in I'mnt of rliinophores, more sparsely soattered on the mid-dnrwal rcgicm 



Khinopliores perfoliate, cylindro-conical, nonretractile within slieaths, of which no trace is present. 

 Thickest below, the smooth, tapering shaft passing gently upward into the conical clavus (pi. xxi, 

 tig. 98). In front the rhachis of tlie clavus is smooth, behind and laterally are borne about 20 

 slightly ohi;(|ne [■latc;^, the pairs ijicclinLi: behind at averyobtu.se angle. The upper plates extend 

 farther aniun. I the .hiMis ihan the l.i«,i niies, the extent on the sides and in front decreasing regu- 

 larly from aUovr .I.ih nwai^l, th.^ l..\\i-st liciiig Init slight posterior ridges. Clavus nearly three-fourths 

 the total lengtli of tlie rlunophure, thi' w IimI,. ni-.jan not being as long as the surrounding dorsal papillie. 



Branchial plumes 7-14, entirely sipaiaie al the bases, arranged in a wide semicircle or an- 

 approaching honseshoe form, the ends .lirect.-.l .ihUijuely backward (pi. .\xxi, fig. 24). The plumes 

 are nearly erect, simply pinnate and free ironi spii-ules. 



Anal opening small, inconspicuous, situated at the center of the arc of branchise. Renal opening 

 very minute, rounded, situated at the right and slightly in front of the anal opening and about 1 mm. 

 distant from it. 



Re] ■roductive oi)enings inconspicuous, on right side far forward, on a line with the bases of the 

 rhiniiphcires, immediately below the outermost row of papilla>. 



Color e\ei ywliere a beautiful deep rose pink (pi. .xxxi, fig. 24). 



Length of larm- iii(li\ iilual 29 mm., width 1(5 mm., and height of bo<ly alone 5 mm. Length of 

 longest d(jrsal papilla- is mm. 



In alcoholic material the pseudo-peritoneum is white, in living specimens slightly pinkish. The 

 blood gland is single, large, broad, and thin, in general outline quadrangular. It fits closely in behind 

 the central nervous system, extending down in lobules between the underlying organs. Length 

 3 mm., width 2 mm. 



The pharyngeal bulb is short and thick, being almut I'.l mm. in length by 2 mm. in width and 

 the same in height, or, including the sucking crop, '■> mm. in height. At the lower posterior border 

 the radula sac projects as a slightly curved, cylindrical process with rounded extremity for a distance 

 of about l.r> mm. On the dcjrsal surface of the pharyngeal bulb is borne a strong ellipsoidal suckinL' 

 crop, 2 mm. long, 1.5 mm. wide and 1.5 to 2 mm. high, attached at its extreme anterior end by a very 

 short narrow petiole. Its walls are very thick and muscular and are lined with a strong cuticula. 



The lal)ial disc has a thick cuticula bearing a I'lng of short thickened rodlets in very close arrange- 

 ment (pi. XXI, fig. 99). The rodlets are circular to elliptical in outline, narrowest at the outer and 

 inner margins and increasing in width toward the middle of the band. Width of the labial armature 

 0.4 mm., diameter of widest rods 0.01 mm. 



liadula narrow, the teeth in 16 rows. Rhachis extremely narrow, iiakid. Pleural tooth (pi. xxi, 

 figs. 100, 101) large, erect, long, flattened, its base triangular, broad, thickened ifbove, in length one- 

 third to one-half that of the whole tooth, the shaft flattened, blade-like, in cross section the shape of 

 a saber blade, its posterior border straight, beveled, sharp, the anterior border thickened, curved and 

 rounded; at the distal end is borne a small posteriorly curved blunt hook. In the older teeth of the 

 anterior end of the radula this hook is often broken off (fig. 100) and the whole tooth is more slendei- 

 than those from the posterior portion (figs. 100, a, 101). Total length of average pleural tooth 

 0.63 mm., length of blade 0.339 mm., length of hook 0.036 mm. The single uncinal tooth (pi. xxi, figs. 

 100, r, 102) is much smaller, thin, depressed, nearly horizontal, triangular in form, the anterior 

 lower edge emarginate, tlie posterior one more or less pointed and often divided into a series of 

 irregular denticles (fig. 102). This tooth is quite variable in form and is easily overlooked. Length 

 O.OMI t.i (1.096 mm., greatest width 0.076 mm. 



Ksiiphagus narrow, about 0.5 mm. in diameter by 5 miu. in length, passing obliquely downward 

 and backward in the median line to the anterior lower end of the visceral mass, where it dilates into 

 the stomach, which is almost entirely inclosed by the liver, into which it sends numerous large diver- 

 ticula. The pyloric end narrows into the intestine at the anterior upper end of the visceral mass, 

 which describes an abrupt loop forward to the right in contact with the superior surface of the anterior 

 genital mass, and then courses directly backward to the anus as a thin-walled tube, 1 mm. in diameter 

 at its anterior end and rapidly tapering to a diameter of 0.5 mm. for the greater part of its total length 

 of al)out 10 mm. 



The liver is about 7 mm. long by 3 mm. wide by 25 mm. high, depressed, its upper face convex, 

 the lower flattened, the i)osterior end slightly conical, rounded, the upper anterior margin occupied by 



I 



