423] PSEUDOPHYLLIDEA FROM FISHES— COOPER 135 



bothria in his rather brief description, which is inadequate for diagnostic pur- 

 poses. Consequently an attempt is here made to better define the species so 

 far as can be done with the poorly preserved alcoholic material referred- to 

 immediately above. 



In general appearance the worm arrests attention on account of the very 

 closely arranged posterior genital segments, which give that part of the stro- 

 bila a transversely plicate aspect. On closer view the anterior segments with 

 their " salient " posterior borders and the characteristic scolex are seen (Figs. 

 26, 62). The latter was described by Linton as follows: 



"Head cuneate, tetrangular, truncate in front, tapering posteriorly into 

 a cylindrical neck-like part near posterior, then expanding so that the posterior 

 end of the head resembles one of the anterior segments of the body. The 

 general appearance of the head when viewed laterally [surficially] is there- 

 fore somewhat like a ball-bat, the constricted part representing the handle. 

 Two longitudinal fossae [bothria], laterally placed, extend from the anterior 

 part of the head to the constricted part. Each of the marginal lobes thus 

 form.ed is indented at the anterior extremity by a short but deep [only in 

 much contracted m.aterial] secondary fossa, which together with the two lateral 

 fossae, give the head when viewed in front a four-lobed appearance. The edges 

 of the lobes bordering the lateral fossae [the walls of the bothria] are thin- 

 hpped and flexible; anteriorly there is a transverse elevation forming both a 

 lateral and a marginal rim and making an obtuse angle between the front and 

 the side of the head. " This is the pyramidal or somewhat conical terminal 

 disc, so characteristic of the scolex. (Figs. 26, 27). The walls of the bothria are 

 "thin-lipped and flexible" only when protruded considerably; in moderate 

 states of contraction, that is, nearest to what the WTiter considered to be the 

 probable state of rest, they are comparatively thick and especially so in the 

 posterior half of the scolex where in consequence the bothrium is reduced to 

 a narrow vertical sHt. "The marginal lobes, when at rest, have a rounded 

 outline, fullest in the middle, tapering posteriorly, appressed sUghtly anteri- 

 orly, and raised into two small eminences on each side of the secondary fossae. 

 The head in a marginal view is somewhat flask-shaped. Seen from the front 

 the head is squarish, with the angles rounded and the sides deeply cleft, the 

 clefts rounded, the lateral clefts deeper than the marginal. " 



As regards the segments Linton in continuation stated that: "Immediately 

 back of the head the segments are very narrow, and for a greater or less dis- 

 tance, depending on the state of contraction, maintain about the same width 

 as the base of the head. In some individuals the small anterior segments con- 

 tinue much farther back from the head than in the one figured. The segments 

 are alternately short and long. This characteristic is quite plainly marked 

 in the segments which immediately foUow the head, is still noticeable on the 

 median segments and also on the posterior ones, but is not so plainly marked 

 on the latter as on the two former. " This is due to the manner of subdirision 

 of the segments which is carried out in the same way as in B. scorpii and B. 

 cuspidatus. It can be followed with certainty, however, only in the " anterior " 



