34 



PROCEEDINGS OF THE NATIONAL MUSEUM. 



VOL. 55. 



Calcareous corpuscles are numerous in the neck and less so in the 

 head. 



Male genitalia. — There are about 300 testes visible in stained toto 

 mounts. Near the middle of the segment they are scattering and 

 are commonly elongated in the transverse axis of the worm (fig. 38) ; 

 in that part of the median field adjoining the longitudinal canals 

 they are crowded close together and appear to be of more irregular 

 outline and looser texture. The testes decrease in number toward 

 the median stem of the uterus, but only occasionally leave a narrow 

 clear field at this point, two or three testes usually occupying this 

 field. Along the lateral portion of the median field they form a 

 confused mass which presses in on the ovaries laterally, but does 



I not extend pos- 

 / terior of the 

 ovaries or the 

 vitellarium. 

 The t e s't e s 

 crowd close to 

 the vas defer- 

 ens and the 

 vagina, leaving 

 only a narrow 

 free field in 

 that region 

 with an occa- 

 sional testis occurring in this field. Anterior of the ovaries the testes 

 leave a free semicircular space, the ends of the semicircle following 

 approximately the antero-lateral borders of the ovaries. The vas def- 

 erens begins at a little distance from the median stem of the uterus 

 on the pore side and extends to the cirrus pouch in a series of some- 

 what irregular loops, an occasional loop in some segments crossing 

 the vagina. The cirrus pouch is 450 to 550 pL long, the inner end 

 being near the outer margin of the ventral excretory vessel. 



Female genitalia. — The ovaries (fig. 38) are of notably loose and 

 open texture, the one on the aporal side of the segment being the 

 larger and frequently extending a projecting portion anteriorly and 

 medially. The ovaries are elongated in the transverse axis of the 

 segment and are concave on the median face, inclosing as a rule a 

 rather circular interovarian space. The vitellarium is a very open 

 reticular structure, elongated in the transverse axis of the segment, 

 not extending as far laterally as the ovaries and very little or not 

 at all between the ovaries. The reticulations of the vitellarimn 

 are also uniformly elongated along the transverse axis of the seg- 

 ment. The shell gland is small and distinct, and not in apparent 



I mm. 



Fig. 38.— Taenia ovis. Mature segment. After Ransom, 1913. 



