474 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [22] 



Several young specimens were obtained, measuring from 5 to 20 mm in 

 length. In these the bothria were identical in shape and habit with 

 those of the adult. In the younger specimens, however, the part of 

 the head to which the bothria are attached was proportionally larger 

 than it is in the adult. In the larger specimens of young the laciniate 

 segments occurred throughout the entire length ; in smaller specimens 

 they occurred only near the head and at the posterior end, while the 

 intermediate parts of the strobile were unsegmented or marked with 

 faint transverse lines. In many of the smallest forms there were no 

 laciniate segments, while the posterior end of the strobile carried a num- 

 ber of elongated segment-like bodies, totally unlike the segments of the 

 adult. These pseudo-segments are evidently evanescent. (Plate III, 

 Fig. 17.) 



Habitat. — Sand Shark [Odontaspis littoralis), in spiral intestine, young 

 and adult together, abundant, chyle swarming with free proglottides. 

 July and August, Wood's Holl, Mass. 



Phoreiobothrium,* gen. nov. 



Near Cylindrophoi'us Diesing. 



Tetrabothrii Spec. Wagener. 



Cylindrophorus typicus Diesing, Revis. d. Ceph. Ab. Par., p. 204. 



Tetrabothrium Carcharice Rondolettii Wagener, Nov. Act. Nat. Cur., xxiv, 



Suppl. 4 and 84, tab. xxii, 270-273; Statu larvae Wageucr, 1. c. 4 aud 84, 



tab. xxi, 266-268, tab. xxii, 2G9. 

 "Genus hoc insutlicieuter cognitum provisorio modo nomine Cylindrophori 



notavi" Diesiug. 



Body elongated, articulate. Head separated from the body by a neck. 

 Bothria four, opposite, tubular, parallel, entire, each armed with com- 

 pound hooks and provided with one supplemental disk (auxiliary ace- 

 tabulum) in front. Minute spines on neck, or on neck and body. Gen- 

 ital apertures marginal. 



Phorelobothrium lasium,i gen. et spec. nov. 



[Plate IV, Figs. 24-29.] 



Head separated from the body by a neck. Bothria four, marginal, 

 Hat-tubular, subrectaugular in outline, each with two compound hooks 

 placed anteriorly, and one auxiliary acetabulum in front of hooks near 

 the lateral edge of the bothrium. Face of the bothria hollowed out, 

 with a thickened or raised border, so that each bothrium resembles a 

 shallow tray. Inner edges of bothria united by a thin membrane, in 

 which lie bands of fibrous tissue. Posterior end of the bothria ellip- 

 tical, with a thickened ring or border, and marked with stria? parallel 

 with the smaller diameter. These striae, when highly magnified, prove 

 to be low ridges, which give to the end of a bothrium the appearance 

 of a coarse rasp. These stria 1 or ridges are not seen plainly unless the 



* Qopelov = a tray. x AaaioQ — bristly. 



