762 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [44] 



Many were from 1 to 2 mm in length, and one very slender one 3 mm . The 

 cirri are provided with short, sharp pointed, broad-based, recurved 

 spines. Their length is about .005 mln . They are inserted on an epider- 

 mal investment of the cirrus, which is easily detached. 



Some of the vessels of the water vascular system can be seen when 

 the specimen is made transparent in glycerine or oil of cloves. Two 

 large spiral vessels were seen in the neck near the head. A short dis- 

 tance back of the head they appear to lose their spiral character. In 

 the head they divide and send branches through the pedicels to the 

 bothria. 



Anatomy of mature segments.— Fascicles of longitudinal muscle fibers 

 were observed in sections of mature segments. These, which were stained 

 deeply with carmine, differ from the longitudinal muscles which I have 

 thus far observed in the Cestods in being distinctly and abundantly nu- 

 cleated. The fascicles, indeed, appear to be made up principally of small 

 fusiform muscle cells, which are about .0014 mm broad and ,0055 mm long. 

 The fascicles themselves vary in breadth from .005 to .014 mm , with vary- 

 ing intervals between approximating the breadth of the fascicles. The 

 intervals between the fascicles are filled with granular tissue. Outside 

 the fascicular layer and outside of this again is a layer which contains 

 fiue transverse, circular, and longitudinal fibers. The circular fibers lie 

 outside the longitudinal fibers. 



In the free segments the ovaries are seen as large lobed organs lying 

 symmetrically on each side of the median line. The middle of the seg- 

 ments is crowded with ova. Near the margins, on each side, are the 

 granular masses of the testes, while near the anterior end is a large 

 convoluted tubular mass, made up,'for the most part, of the voluminous 

 vas deferens. The cirrus is of extraordinary length and quite slender. 

 When retracted, the sheath extends into the interior of the segment, its 

 base lying close to the posterior folds of the vas deferens. The latter 

 in section is seen to be packed with exceedingly fine fibrous material, 

 which appearance I take to be due to the presence of spermatozoa. 



The course of the vagina was not satisfactorily traced throughout its 

 entire extent. Its external opening is immediately in front of the cirrus, 

 there being, in fact, but a single external opening for the genital or- 

 gans. It lies close beside the front edge of the cirrus sheath. At the 

 base of the latter it changes its course from one at right angles to the 

 axis of the segment and is inclined gently towards the front end of the 

 segment. I have not yet succeeded in tracing it in a continuous line to 

 the ovary, but in several sections the vaginal tube was seen both near 

 its outlet and in the midst of the lobes of the ovary. It seemed to dis- 

 appear in the vicinity of the vas deferens. As only mature segments 

 were cut into sections, it seems probable that the tissues of the vagina 

 had already been absorbed to a considerable extent in its middle 

 course, in order to give room for the ova, which are not confined to a 

 definite uterus, but appear to fill the whole inner cavity of the segment. 



