772 KEPORT OF COMMISSIONER OF FISH AND FISHERIES. [54 



length, 25""" ; breadth, 1 to 1.5 ml " ; genital apertures marginal; cirru 

 echinate. 



Habitat. fihinoptera quadriloba; spiral valve; three specimens 

 Wood's Holl, Massachusetts, July 20, 1887. 



The three specimens which furnish the data for the. present descrij 

 tiou were found in the posterior fold of the spiral valve of the 

 nosed ray (Rhinoptera quadriloba). 



When first placed in sea-water they were rather active. The 

 tended bothria gave the head somewhat the appearance of a pel tat 

 leaf. The face of each bothrium is divided into twenty-one pits or locul 

 The arrangement of these loculi in every case in the living specimen 

 appeared to be definite and the number constant. There is first 

 longitudinal row of five comparatively large loculi, occupying the mir 

 die line of the bothrium; then a small pit at each end, and seven pit 

 on each side, making twenty-one in all. The loculi are larger toward 

 the posterior end of the bothria than they are in front. In alcoholi 

 specimens the edges of the bothria are curled inwards so that it is no 

 always easy to count the exact number of loculi. The characteristi 

 appearance of a circle of about sixteen loculi around the circuuifereuc' 

 of the bothrium and a longitudinal row of five at the bottom of the fac< 

 of the bothrium can be made out in most cases. In one of the speci 

 ineus, when cleared up in oil of cloves, there appeared to be eighteei 

 loculi around the border, which, together with the five central ones 

 would make twenty-three instead of twenty-one. From this circum 

 st'ance I am therefore as yet in some doubt as to whether the numbe 

 of loculi is always constant. The ribs which outline the loculi are thicl 

 and muscular and give to the margins of the bothria a creuulate out 

 line. The pedicels are very short and thick. The bothria are lateral 

 their posterior ends rather thick and slightly flaring. In consequent 

 of this the head of alcoholic specimens is sagittate in marginal, squarisl 

 in lateral view. In the living worm, when at rest, the bothria an 

 elliptical. 



The first segments begin as fine transverse wrinkles. In one speci 

 men the first distinct segments began about l ium back of the head anc 

 were .03 nnn long and .4""" broad. What appears to be a characteristic 

 of the species is the occurrence at short intervals of very distinct trans 

 verse lines which divide the body into pseudo segments. These upoL 

 superficial examination might be mistaken for true segments. When 

 examined carefully, however, they are seen to be made up in each case 

 of a number of true segments. In one specimen the first of these trans 

 verse lines appeared 3.2 mm back of the head, the next 3.8 mm , and follow 

 ing this two others 5 and 7 1U1 ", respectively, from the head. These pseudo 

 segments are formed in some cases by the natural division between twc 

 segments becoming very distinct, in others by an entire segment be 

 coming thin and transparent. 



Following are the measurements, in millimeters, of a living speci men 



