[27] ENTOZOA OF MARINE FISHES OF NEW ENGLAND. 479 



Millimeters. 



Length 0.74 



Length of posterior segments 1.90 



Breadth of posterior segments 0. 84 



In another specimen : 



Length of posterior segments '. 2. 20 



Breadth of posterior segments 0. 78 



Number of joints in onespeeimen about 342, the last 11 of which were 

 mature. 



There was one prominent, transverse rib at about the posterior third 

 of each bothrium ; another, much less prominent, about the middle, at 

 the extremities of the iuner pair of recurved hooks, and two other 

 faint, transverse lines, parallel with the ribs and apparently homolo- 

 gous with them, between this and the base of the hooks. The trilocu- 

 lar auxiliary acetabula showed but faintly in«most of the specimens. 



There is considerable difference between the anterior segments of the 

 specimens examined and those figured by Van Beueden (Vers Cesto'ides, 

 tab. xii). In Van Benedeu's figures the anterior segments are repre- 

 sented as beiug several times as long as broad, and with the flaps rudi- 

 mentary and rounded. The sketches of the head and anterior segments 

 (Figs. 1, 2) were made from a mounted specimen. The proportions are 

 identical with those of the living specimens, as is proved by comparing 

 these sketches with some memorandum sketches made at the time of 

 collecting. Amoug all the specimens, eight or ten in all, not one was 

 noticed in which the segments differed materially from those repre- 

 sented in the figures. In Wagener's figures (Entwick. d. Cestoden, 

 tab. xxii, fig. 274) the proportions of the anterior segments are about 

 the same as I have found them. The transverse costal of the bothria 

 do not agree exactly with the figures of Van Beneden and Wagener, but 

 the differences are so slight, that I have no hesitation in pronouncing 

 the specimens which I have examined identical with those figured by 

 Van Beneden and Wagener. 



Family DIBOTHRIORHYNCHID^E Bicsing. 

 Rhynchobothrium Budolphi. 



Tcenice spec. Fabricins. 



Bothriocepliali (Rhynchobothrii) and Tetrarhynchi spec. Rudolphi- 



Botliriorhynchus Van Lidth. 



Rhynchobothrium bisulcatum, sp. nov. 



[Plate IV, Figs. 9-23.] 



Head subcorneal, bluntly rounded in front. Bothria two, lateral, 

 separating slightly at posterior corners, coalescing in front, each di- 

 vided into two distinct lobes by a median sulcus, which extends from 

 the posterior border about one- fourth the length of the bothrium, where 

 it divides into two less distinct but clearly marked sulci, which diverge 



