60 ILLINOIS BIOLOGICAL MONOGRAPHS [348 



the color of the pigment being dark bro-wn. Ahho 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 WTiter is aware. It would seem, 

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

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

 cirrus-sac of Bothrimonus pachycephaliis 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 hned with a continuation of the cuticula 

 of the female genital cloaca, 5/i 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 senrdnal receptacle is provided 

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

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

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

 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 lunbs 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 surrounding the central connections of the genital ducts and the coils of 

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

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

 isthmus 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 15/i in diameter, their nuclei 7 to 8/i and 

 their nucleoH 4^, those of the latter species being 9 to 12/Lt according to Grimm 

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

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

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

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

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



