Nos. IAND2.] COTYLASPIS INSIGNIS. 27 



vesicle, crosses to the right side of the body under the intestine 

 and runs backwards to the spermary .which is a single large glob- 

 ular organ located under the intestine and near its posterior end. 

 In the female system we find (Fig. 3) a winding uterus enlarged at 

 intervals by the enclosed eggs. The uterus may pass from the 

 left to the right side under the intestine, or it may be shorter and 

 remain on the left side, but in either case it finally passes from 

 the left to the right under the intestine and thus reaches the yolk 

 duct, passing on as the oviduct and " tuba fallopii " to finally reach 

 the ovary. This lies under the diaphragm on the right side. The 

 only organ entering the passage to the ovary is the duct from 

 the yolk receptacle, there being no shell glands or Laurer's canal. 

 The yolk receptacle is a triangular chamber at the junction of the 

 right and left ducts from the vitellaria, which are a number of 

 small glands on each side of the body close to the ventral surface. 

 A detailed account of each of these parts will now be given. 



ii. Tlic Male Organs. 



The spermary is single as it is in Aspidogastcr and Macraspis, 

 while in Cotylogastcr and Stichocotyle there are two. It lies 

 directly below the intestine (Sp., Fig. 8) and a little in advance of 

 its posterior end. It is just above the muscles of the ventral 

 sucker, below the excretory collecting vessel, and behind the 

 yolk receptacle. In specimens under compression it is pushed aside 

 by the intestine and generally appears on its right. It is spherical 

 and its diameter varies between 0.26 and 0.18 mm. It has a dis- 

 tinct wall (Fig. 37) in which are scattered nuclei, and in which 

 muscular fibers are recognizable after iron-hsematoxylin staining. 

 This muscular tissue is very scanty unlike Aspidogaster, in which 

 Stafford finds a longitudinal and a circular layer. A layer of cells 

 lies in contact with the wall, parietal cells (Figs. 38 and 40), and 

 the interior is occupied with free "central cells" .which show 

 stages of spermatogenesis in some of my series. The latter are 

 developed from the former. Two stages of the organ have thus 

 far come to my notice, viz., a " resting stage," in individuals killed 

 in May, and an " active stage," in animals killed in July and 

 August. In the former, the resting stage, the parietal cells, as in 

 Fig. 38, show a large and distinct nucleolus excentrically located 



