792 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [74] 



The posterior segments of corresponding degree of development in 

 the two sorts do not differ materially in their anatomy. 



Anatomy of posterior segments.-^- The posterior segments of the al- 

 coholic specimens are opaque near the margins and transparent along 

 the median region. The opacity of the marginal regions is due to great 

 numbers of granular bodies about .03 mm in diameter. These marginal 

 granular masses evidently represent the vitelline glands. The ovaries are 

 two pale, oval organs lying one on each side of the lateral line at the pos- 

 terior end of the segment. Each is about .28 mm long and .15 nim broad. In 

 section, when highly magnified, tlie ovaries are seen to be made up of 

 small polygonal cells about .005 mm in diameter. The vagina opens im- 

 mediately in front of the cirrus. The two organs have a common ex- 

 ternal opening, situated near or a little in front of the middle of the 

 margin. The vagina at first follows the front side of the cirrus bulb, 

 and then continues as a much convoluted tube, in an irregularly sinu- 

 ous course to its termination in a bulbous enlargement between the 

 lobes of the ovary. An elongated and rather broad organ, appearing 

 in section to have ruffled or lobed margins, occupies the middle of the 

 segment, extendiug from the ovary nearly to the anterior edge of the 

 segment. In longitudinal sections this organ shows a number of empty 

 spaces and others filled with fine granules: I take it to represent the 

 uterus, as yet destitute of ova. The vas deferens is a voluminous, con- 

 voluted tube lying near the anterior end of the segment and adjoin- 

 iug the base of the cirrus bulb. In sections this organ was densely and 

 finely striated, due as I infer to the spermatozoa which fill it. No ova 

 were found in any of the segments. 



The cirrus is of moderate length. As it was retracted in every case 

 its exact length could not be ascertained. One was estimated to be 

 ,25 mm in length ; the diameter of the base was in one case .036 mm , in 

 another .03 mm . Another was .38 mm long, diameter of base .05 mm , middle 

 ,027. ram The cirrus bulb is pyriform, its length equal to about one-third 

 the breadth of the segment, the large end inward. The cirrus is covered 

 with minute, recurved spines which are about .092 mm in length. When 

 highly magnified the margins of the segment are finely serrate. 



Anatomy of head and neck, — Transverse sections of the head and part 

 of the neck of a, specimen stained with carmine furnished the following- 

 data : 



The superficial tissue of the bothria is mainly granular. The thick- 

 ened, crenulated border is composed of short radiating fibers with a few 

 longitudinal interspersed and a layer of circular fibers as its base. Very 

 coarse muscular fibers ,005 mm in diameter, which originate by the split- 

 ting up of the large fascicles of longitudinal muscles of the neck, radiate 

 from the center of the head, and constitute the predominant tissue of 

 the two pedicels. The vessels of the water vascular system apparently 

 originate at that part of the bothria where the edges of a marginal pair 

 approach each other. 



