TAPE-WOEM. 



133 



Fig. 69. 



In its size it varies considerably ; it consists of two muscular coats 

 invaginated one within the other, and unrolls itself like the finger of a 

 glove, until it acquires its full length. The external surface, which is 

 internal when in a state of re- 

 pose, is covered with minute 

 asperities or rough points ; when 

 fully retracted, it is lodged in 

 the pouch, e. 



(345.) The female generative 

 system is composed of an ovary, 

 which produces the germ (ger- 

 migene), of an organ which 

 secretes the vitelline globules 

 (vitelligene), of ducts from these 

 two organs, and of a matrix, a 

 copulative vesicle, vagina, and 

 vulva. 



(346.) It seems to have been 

 by no means a rash supposition 

 on the part of Siebold, that in 

 some Entozoa there might exist 

 a double set of glands for the 

 production of the ova, one ap- 

 propriated to the formation of 

 the germ, the other to the secre- 

 tion of the vitellus. In the 

 Cestoid forms, according to Van 

 Beneden, the proper ovary or 

 germigene (fig. 69, i) is situated 

 at the posterior part of the body, 

 occupying about one-third or 

 one-quarter of its width. This 

 organ is double, being exactly 

 repeated on the right and left of 

 the median line, the two being 

 united by a central commissural 

 canal*: when empty, the pre- 

 sence of this organ is discover- 

 able with difficulty, on account 

 of its extreme delicacy. Its appearance varies much : sometimes it is 

 a bag surrounded with slight depressions (culs-de-sac) ; sometimes the 

 whole viscus is divided into lobes, and has the appearance of an ordi- 

 nary gland, whilst occasionally it is entirely made up of long ciecal tubes 

 united together, and opening at the same point. 



* It is represented in the figure upon one side only, to avoid confusion. 



Diagram representing the fully-developed gene- 

 rative system of the Proglottis of a Cestoid Ento- 

 zoon (after Van Beneden). a, testis; b, com- 

 mencement of ditto; c, vas deferens; d, penis ; 

 e, sac of the penis ; f, orifice of vagina ; g, vagina ; 

 k, copulative vesicle; i, germigenous organ, or 

 ovary (represented on one side only); ?,germiduct; 

 TO, point at which the vitelline globules enter the 

 germiduct; n, vitelligenous organ, or vitelliduct; 

 o o, transparent vesicles, developed at a very early 

 period ; p, oviduct ; q, matrix ; r, longitudinal ca- 

 nals ; *, the skin ; t, cutaneous glands. 



