45] LIFE HISTORY OF TREMATODES— FAUST 45 



In Cercaria pellucida the well-developed cirrus pouch and the poorly de- 

 veloped vagina reach the confines of the excretory trunk just behind the median 

 eye. In C. konadensis the cirrus pouch and the vagina are both equally devel- 

 oped. The former is falciform, the later pyriform. The vagina is lateral 

 to the cirrus pouch but is somewhat posterior to it. The genital pore in 

 C. pellucida is not as far posterior as that in C. konadensis. In this species, 

 as well in C. urhanensis, the testes are marked by definite cell masses, while 

 in C. konadensis the testicular masses are much more indefinite. They are 

 small in each case and lie ventral to the vitelline organs. The course of the 

 vasa efferentia is clearly outlined. 



On the basis of the structure of the vitellaria alone these species can be 

 differentiated in the cercaria stage. In C. pellucida the glands are actually 

 spiculate in outline, flattened dorsoventrally. The vitelline material is 

 finely granular and closely massed. In C. konadensis the glands are decidedly 

 dendritic, and the granules are diffuse. In C. urhanensis the glands are lobate 

 and the fine granules are included within a dense mucoid matrix. 



B. Holostomata. The genitalia of the Holostomidae and Hemistomidae 

 will be considered separately. 



1. Holostomidae. The thickness of the tetracotyle larva, together with 

 the thickness of the cysts, in which the majority of these individuals have been 

 found, has prevented a study of the genital system from stained toto mounts. 

 However, these organs come out clearly in frontal sections of 7/i thickness 

 (Fig. 39). In Cercaria flabelliformis the ovary is situated just caudal to the 

 posteriormost muscular lappet. A short oviduct proceeds dorsad to the 

 ootype. The uterus winds posteriad to the genital pouch. The vitelline 

 glands are long paired cords. In C. flabelliformis they are composed of large 

 vesicular glands (Fig. 39) ; in Tetracotyle pipientis (Fig. 47) they are loosely 

 follicular. The testes are paired structures which may occupy positions from 

 the plane of the ovary (T. pipientis) to the plane of the genital pouch (C. 

 flabelliformis). The pouch is muscular and opens posteriad, ventral to the 

 excretory pore. 



Thus these genital organs are tj^ically holostome in character, correspond- 

 ing to the main features described for the adults by Brandes (1891), Thoss 

 (1897), and Johnston (1904). They are sufficiently detailed in this stage of 

 the species development to be of diagnostic value. 



2. Hemistomidae. In this family all of the genital organs are situated 

 entirely posterior to the acetabulum. The primitive genital pore, anterior 

 to the acetabulum, has lost its connection with the genitalia, and with the 

 addition of muscular elements has assumed a suctorial function. 



The species Cercaria ptychocheilus has an ovary elongate in a transverse 

 plane, nearly spatulate, situated just behind the acetabulum. It is granulate, 

 compact, and stains deeply with hematoxylin dyes. At its left it merges 

 into the oviduct, a large coiled tubule, which bends on itself three times just 

 behind the margin of the ovary, then empties into the ootype just anterior 



