7G0 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [42] 



The specific name pulvinatum, is retained as descriptive of a common, 

 even if in a measure accidental, condition of the bothria. 



Head cruciform, bothria four, directed forwards. The pedicels of the 

 bothria are short, stout, and conical, bearing on their distal extremity 

 the cushion-like bothria which are nearly circular in living specimens, 

 or shaped like the quadrant of a circle in alcoholic specimens. The 

 margins of the bothria are entire at the base, while their upper edges 

 are frilled or ruffled and their faces thrown into corrugated folds. The 

 bothria do not bear any supplemental disks, and there is no terminal 

 papilla or myzorhynchus to the head. Properly speaking, there is no 

 head, the four pedicels simply originate from the anterior end of the 

 body like so many forks. That is, the neck is abruptly quadrivaricate 

 at its anterior end. 



The neck is long, flattened, somewhat enlarged, both iu breadth and 

 thickness near the head. It is crossed by fine transverse lines which 

 gradually become more distinct and later divide the body into seg- 

 ments. 



The body is long and of approximately the same breadth throughout 

 or, in alcoholic specimens, somewhat thickened medianally. The first 

 segments are very short and crowded, increasing uuiformly in length ; 

 median segments widest, broader than long; first mature segments 

 squarish, then a little longer than broad. Mature segments narrow in 

 anterior diameter, broad behind, at length easily detached. Free prog- 

 lottides somewhat elongated. All distinct segments with posterior di- 

 ameter greater than anterior. Genital apertures marginal ; male and 

 female approximate near middle of margin. Cirrus very long and 

 echinate. 



Length of specimen 550 mm , accompanied with great numbers of free 

 proglottides. 



Habitat. — Trygon centrum, spiral valve; one specimen, with numer- 

 ous free segments. Wood's Holl, Massachusetts, August 1, 1887. 



The specimen which furnished the data for the foregoing description 

 was very much larger than any of the associated species of Entozoa, of 

 which there were several. The length while living was 550 inm , and there 

 were besides, immense numbers of free proglottides, which must have 

 come from this strobile, as it was the only one of the kind found, and most 

 careful and painstaking search was made for small forms. Only a small 

 proportion of the whole number of these free proglottides with which 

 the chyle was swarming was saved. Upon counting the number, how- 

 ever, I find that there are about two hundred of them. 



My notes made at the time of collecting contain this description of 

 the head : Seen from the under side, each of the four bothria rises from 

 a short, smooth, conical pedicel, which enlarges rapidly toward the dis- 

 tal end. The outer half of the length is made by the frilled and puffed 

 margin of the cushion-like bothrium, which at first projects abruptly 

 about midway from the base of the pedicel to the outer surface of the 





