NO. 2258 TAENIOID CESTODES OF DOGS AND CATS— HALL. 



25 



in the median field, except in the region near the ovary where the 

 clear field is a little wider. On the pore side of the segment they 

 extend back to the vas deferens, the space between the vas and the 

 vagina being free of testes, and then extend from the vagina on this 

 side, and from the anterior margin of the segment on the aporal side, 

 back to the posterior margin of the segment. They press between 

 the loose lobes of the ovary and posterior and dorsal of the vitel- 

 larium. Aside from the space occupied by the median stem of the 

 uterus and the field of the vas deferens and vagina, the only space 

 free of testes is that between the ovaries. The testes are arranged 

 in two strata, a dorsal and a ventral, some overlying others in frontal 

 views. The vasa effer- 

 entia open into a dis- 

 tinct vesicula semi- 

 nalis, 210 by 350 \i in 

 diameter, located on 

 the pore side of the 

 median stem of the 

 uterus. From the 

 vesicula seminalis the 

 vas deferens extends 

 posteriorly parallel to 

 the median stem of 

 the uterus for a short 

 distance and then 

 curves t o w a r d t h o 

 pore side of the seg- 

 ment. The vas def- 

 erens is very large, 

 much looped and 

 irregular, with the 

 thick loops lying very 

 close to one another. 

 The cirrus pouch extends in from the margin of the segment to the 

 plane of the ventral excretory canal, or very commonly to a point as 

 much as 107 n median of this plane, and is surrounded by a dis- 

 tinctive layer of cuboid cells. It is cylindrical or. rather, compressed 

 elliptical in outline, with its maximum diameter in the middle. 

 Maximum diameter, 130 to 140 [x ; length, 460 to 800 [>.. 



Feinale genitalia. — The ovaries (fig. 31) are somewhat reniform, 

 the concavities of the two inclosing an oval interovarian field, and 

 are of rather loose structure. They are very nearly equal in size. The 

 vitellarium is very large, extending laterally past the ovaries, and 

 forward to the posterior border of the ovaries and a short distance 

 into the interovarian field. The shell gland is large and in frontal 



Fig. 31.— Taenia pisitoemis. Mature segment. 

 After Deffke, 1891. 



Enlarged. 



