. 4 
480 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [28] — 
7 
and inclose two sides of a triangular space. At the extreme anterior 
end of each of these secondary sulci is situated one of the four probos- 
cides. Hach bothrium is broadly convex on the posterior border, with 
often a slight emargination on the posterior edge of each lobe. Each 
lobe is triangular, the posterior side being the posterior edge of the 
bothrium, the outer side being the marginal edge of the bothrium, and 
the inner side being bounded by the median suleus and one of its 
branches. The central portion or fave of each lobe is sometimes de- 
pressed, which gives rise to the appearance of a double furrow on each 
side of the median triangular piece. Posterior edges of bothria thick 
and fleshy, overlapping the neck. Neck tubular, conical, sometimes 
slightly swollen back of the head, a little shorter than the bothria, the 
posterior fourth prolonged into a collar, which incloses the anterior part 
of the body and its articulation with theneck. Proboscides (trypanorynchi 
Dies.) four, a little shorter than head, armed with numerous hooks 
arranged in spirals, about eight visible in each spiral; spirals about 
0.02"™ apart. Hooks recurved, pointed, broad at base in an antero- 
posterior direction, very thin from side to side, those near the base of 
the proboscis shor ter-curved and blunter than the others. Proboscis 
sheaths straight in front, but with a single short spiral curve at the 
posterior end where they join the contractile bulbs, with one of which 
each is connected. The four contractile bulbs, which lie side by side iii 
the neck, are about twice as long as broad and about one-half the 
length of the neck. The distance between the point of articulation be- 
tween the neck and the body and the posterior end of the contractile 
bulbs is normally about one-third the length of the latter. 
So far as examined the heads presented the same general outline, 
with one exception. In the exceptional case noted there is a slight 
constriction of the bothria where they overlap the neck, at the point 
which marks the greatest diameter of the head in all the other speci- 
mens. This imparts to the head a more rounded outline in front than 
in the others, and a less diameter proportionally at the base of the 
bothiia. 
The body, usually very much attenuated anteriorly, is unjointed for 
a short distance back of the head. Fine transverse lines soon make 
their appearance, and shortly afterwards the first segments are formed. 
The latter are usually much broader than long, and rectangular in out- 
line. Although they sometimes are lengthened with rounded corners, 
so as to give to the series of segments a beaded appearance.: 
The mature proglottides are always squarish, or rectangular, some. 
times longer than broad, sometimes broader than long. The male gen- 
ital openings are marginal, irregularly alternate, always near ‘the an- 
terior edge of the proglottis. Female genital openings lateral, median 
dehiscent, apparently not appearing until the proglottides are almost 
ready to separate. 
Length of strobiles with mature proglottides from 40™™ to 230™", 
