60 ILLINOIS BIOLOGICAL MONOGRAPHS [348 



the color of the pigment being dark brow-n. Altho they are very closely ar- 

 ranged around the wall of the cirrus-pouch and most of them are quite pointed 

 towards the same, their function is pretty much a matter of conjecture; unless 

 perhaps they are the much modified myoblasts of the muscles of the walls 

 of the pouch. This is suggested by the intimate relations of the inner at- 

 tenuated ends of some of them with the latter. No such cells have been de- 

 scribed for the European species, so far as the writer is aware. It would seem, 

 however, that certain "radiar gestellten, kolbenformigen Driisen, " merely 

 mentioned and figured by Linstow (1904:308, Fig. 26) as surrounding the 

 cirrus-sac of Bothrimonus pachycephalus Linstow, are similar to these peculiar 

 cells. But in the latter species they are evidently much less extensive than in 

 C. americanus. Similar glandular cells were also described by Schneider (1902: 

 76) for Bothrimonus nylandicus Schneider. 



From its opening which has been dealt with above the vagina proceeds 

 dorsally almost at right angles to the surface of the proglottis, and then within 

 the medulla turns backward with a few coils to expand into a comparatively 

 enormous receptaculum seminis which, on account of its size, can scarcely be 

 distinguished from one of the coils of the uterus. At the turn in its course the 

 duct has a diameter of about 15/^ and is Uned with a continuation of the cuticula 

 of the female genital cloaca, 5ju in thickness, and surrounded by a layer of 

 circular muscles. As it passes above the ovarian isthmus its cuticular lining 

 gradually diminishes in thickness, so that the seminal receptacle is provided 

 with a very thin layer only. While the latter may have a diameter of 75ju slight- 

 ly behind the isthmus of the ovary, it narrows down very abruptly before 

 joining the oviduct to a very small spermiduct, 8ju in diameter and about 25^ 

 in length. In distinct contrast with C. truncatus there is no " connective tissue 

 and muscular sac" surrounding the beginning of the vagina, as described by 

 Kraemer, but only the usual mass of nuclei, most of which are subcuticular in 

 their nature. The ovary (Figs. 82, 93) is a tubulolobular organ, the limbs of 

 which radiate from a ventral isthmus laterally as far as the nerve strands, 

 anteriorly as far as the cirrus-sac, and dorsally thruout the whole of the medulla, 

 thus surroimding the central connections of tlie genital ducts and the coils of 

 the uterus (Fig. 93). The wings, in whose irregularly shaped tubules yoimg 

 ova in various stages of development are to be seen, connect with the rounded 

 isthm.us by narrow portions quite as described and figured by Kraemer, altho 

 he evidently erroneously called the isthmus the "ootyp." The latter 

 in this species has a width of 0.18mm. by a length of 0.10 as compared with the 

 similar measurements of 0.19 and 0.07mm. in the case of C. truncatus. Ova 

 from the isthmus measured from 13 to ISju in diameter, their nuclei 7 to 8/x and 

 their nucleoH 4/^, those of the latter species being 9 to llfx according to Grimm 

 (1871) and 15/i according to Kraemer who gave the diameter of their nuclei 

 as 9jLi. The oviduct begins with a rather short oocapt (Fig. 99), 25/i in dia- 

 meter, and proceeds for only a comparatively short distance, with a diameter 

 of from 15 to 20ju, before being joined by the spermiduct. A Httle farther 

 dorsally it is met by the vitelline duct which comes from the ventral portion of 



