748 REPOKT OF COMMISSIONER OF FISH AND FISHERIES. [30] 



la a mature segment which had been placet! in glycerine, it was seen 

 that the reproductive aperture, in the shape of a prominent papilla was 

 situated at the margin, or rather on the anterior face of the marginal 

 projection. The diameter of the apex of this papilla, which doubtless 

 represents the base of the cirrus, was .16 mm . 



A single small individual (Figs. 2 and 3), found entirely inclosed and 

 free in a cyst-like cavity, which was filled with transparent, watery 

 lymph, as in the case of the others, appears to be a young specimen of 

 this species. In it the bothria are much more elongated than in the 

 others and the head is truncate with a tumid border projecting on all 

 sides and a minute papilla at the apex. Segments in the shape of fine 

 transverse lines begin immediately behind the head. The posterior 

 segments resemble those of the adult. The specimen is, in fact, a small 

 copy of the larger ones whose bodies were dependent from the inner 

 walls of the rectum. The dimensions obtained from measurements of 

 this small specimen while it was still alive are as follows : 



Millimeters. 



Length 13.0 



Breadth of head at apex 1.2 



Length of bothrium 3. 



Breadth of bothrium 1.2 



Diameter of neck 2. 



Length of posterior segments 1.0 



Breadth of posterior segments 1.5 



The following data with regard to the anatomy of the segments were 

 obtained from a study of a series of longitudinal and transverse sec- 

 tions of portions taken from the middle and the posterior end of an 

 adult specimen. The appearance of these sections, particularly of the 

 longitudinal ones, is very peculiar and indeed unique among the Di- 

 bothria. In a series of about ninety longitudinal sectious carried 

 through a piece taken from the posterior end of a strobile, only about 

 one-third of the number proved to belong to the segments proper. The 

 remaining two-thirds belonged to the prominent posterior edges which 

 lie about .06 mm apart. These edges protrude marginally as well as lat- 

 erally to a distance equal to nearly one-third the total breadth of the 

 strobile. In longitudinal sections, through the middle of the segments, 

 these free edges form a pectinate border on each margin. Such sections 

 resemble a comb with teeth on the two opposite edges. The teeth are 

 of different shapes, some are acute, others club-shaped. These free 

 edges of the segments consist of two muscular walls with a central 

 space, which is filled with irregular granular bodies. The latter are 

 probably a part of the reproductive system. The reproductive organs 

 proper are borne, not exactly on the margins of the segments, but on 

 one of the lateral faces of the marginal projection. The cirrus pouch is 

 very muscular, and in median section is long, oval, or slipper-shaped. 

 The outer part contains the invaginated cirrus, which seems to be a 

 very thick- walled and muscular organ, at least at the base. The inner 



