﻿CESTODE PARASITES OF MAN. 545 



loop within cirrus pouch (fig. 15), is extremely convoluted after passing ventral 

 canal, and ends shortly before reaching median line in distinct dilation (0.075 

 millimeter broad) which receives numerous vasa efferentia; testicles (figs. 8, 9, 13) 

 measure 0.13 to 0.16 millimeter in length ( dorso-ventral diameter of segment) 

 by O.OG to 0.08 millimeter in their transverse diameters. 



Vagina makes two spiral coils before reaching excretory canal (figs. 11, 12) 

 and after passing dorsad of the canal turns sharply ventrad, sweeps posteriorly, 

 and near the median line it dilates to about twice its former diameter to form a 

 muscular receptaculum seminis (0.040 millimeter in diameter) which abruptly 

 enters a large globular chamber (0.16 millimeter in diameter) situated ventrally 

 in the median line between the median extremities of the ovaries and the vitellogen 

 gland and containing immature ova. (Figs. 7, 8, 13, 14.) From the posterior 

 border of the chamber a tubule, 0.05 millimeter in diameter, passes dorsally in 

 a convoluted course, taking up the vitellogen and shell gland ducts, and empties 

 in the dilated posterior extremity of the uterus. 



The vitellogen gland (figs. 8, 10, 13) lies along the extreme posterior border, 

 close against the transverse canal, extending laterally two-thirds the distance 

 from the median line to the ventral canals (1.2 millimeters). On longitudinal 

 section in the median line it measures 0.3 millimeter dorso-ventrally by 0.01 

 millimeter longitudinally, filling the posterior one-tenth of the medullary space. 

 Its lateral extremities are attenuated and lie entirely ventrad to the median 

 saggital plane. 



The ovary (figs. 8, 10, 13) is composed of two unequal, transversely elongated 

 lobes with their posterior and ventral surfaces lying close against the vitellogen 

 gland and the ventral boundary of the medullary layer respectively. Each lobe 

 extends laterally three-fourths the distance from the median line to the ventral 

 canals and is thickest in the posterior half of its median third where it com- 

 pletely fills the medullary space dorso-ventrally. The dorsal surfaces of the 

 lobes are convex, approaching the ventral boundary of the medullary space at 

 their median, anterior, and lateral margins. 



The lesser lobe, proximal to the pore side of segment, is bounded anteriorly by 

 the course of the vagina, except in its median third where, as it approaches the 

 median line, a few filaments may pass ventrad to the vagina and reach a more 

 anterior position. 



The greater lobe, distad to the pore, extends anteriorly to or slightly beyond 

 a transverse plane passed through genital pore; its anterior third is extended 

 across the median line, slightly overlapping anteriorly the inner extremity of 

 the opposite lobe. 



The uterus (figs. 8 to 10) begins posteriorly as a pyriform dilation, 0.45 

 millimeter in diameter, situated obliquely between, but slightly dorsad to, the 

 median borders of the ovarian lobes ; diminishing in size the uterine stem 

 passes obliquely antero-laterally toward the pore side of the segment until it 

 reaches a point posterior to the median extremity of the vas deferens, when it 

 turns inwardly at a sharp angle to its former course and, passing around the 

 extended extremity of the greater ovarian lobe, continues obliquely forward and 

 inward to the median line, which it reaches at about the center of the longitudinal 

 axis of the segment ; it then turns anteriorly and, in a spiral course-, of from 

 four to six closely wound turns, reaches the anterior segmental border. In the 

 spiral anterior limb the diameter of the uterine tube is about 0.035 millimeter, 

 while the spiral fills a space of from 0.080 to 0.130 millimeter, the spiral coils 

 becoming wider as they approach the anterior border of the segment. 



Further development of the uterus (figs. 13, 16 to 18). — In the 500th segment 

 (fig. 13) the dilated posterior extremity of the uterine tube has enlarged to a 

 chamber measuring 0.32 millimeter dorso-ventrally and antero-posteriorly, by 



