42 



PROCEEDINGS OF THE NATIONAL MUSEUM. 



VOD. 55. 



convex lateral margins. There are from 12 to 20 gravid segments, 

 from 6 to 11 mm. long and 3 to 5 mm. wide, usually not over 4 mm. 

 The calcareous corpuscles are very small, 16 to 16 jjl in diameter. The 

 longitudinal excretory canals are small, the ventral lying about 420 [x 

 from the margin of the segment. The genital papilla is rather flat, 

 but is quite distinct as a result of the translucency of this worm. 



Afale genitalia. — There are about 200 testes in one horizontal 

 plane. They are principally confined to the lateral portions of the 



median field near the longitudinal 

 canals, a few scattering testes oc- 

 cupying a more median position an- 

 teriorly, but leaving a fairly wide 

 and distinct field about the median 

 stem of the uterus (fig. 45). The 

 testes do not press close to the field 

 of the vas deferens and vagina, and 

 leave a fairly wide free field on each 

 .side of these canals. They extend 

 alongside of the ovaries but do not 

 press close to them and do not pass 

 posterior of the ovaries in the direc- 

 tion of the vitellarium. The testes 

 are practically confined to the fields 

 lying lateral of lines drawn parallel 

 to the longitudinal axis of the stro- 

 bila through the lateral edges of the 

 ovaries. The vas deferens originates 

 close to the median stem of the uterus 

 on the pore side of the segment and 

 extends in a series of loops to the 

 cirrus pouch. The cirrus pouch usu- 

 ally originates in the field lateral of 

 the longitudinal excretory canals and 

 is either curved, with the convexity 

 of the curve toward the anterior por- 

 tion of the segment, in which case the vagina follows the curve on 

 the concave posterior side, or is straight and more or less piriform 

 or cylindrical, in which case the vagina comes in from the genital 

 eminence to about the middle of the cirrus pouch and then bends off 

 at a right angle or even turns back toward the lateral margin for 

 a short di^ance. The cirrus pouch is 315 to 350 \i. long and is 110 

 to 145 [JL wide. 



Female genitalia. — The ovaries are somewhat elongated along the 

 longitudinal axis of the strobila and inclose an interovarian field 



Fig. 44. — Multicep.s multiceps. Entire 

 STEOBiLA. Actual size. After Hall, 

 1910. 



