Two New Trematodes of the Family Gyrodactylidœ. 5 



approximate number of these gland cells appears to be about 

 thirty. The wide ducts begin one on either side of the body 

 directly behind the intestinal loop, and proceeding backward first 

 on the ventral side of the caudal glands and more posteriorly side 

 by side with and on the outer side of the ducts of the latter, open 

 on the caudal disk; they are of nearly uniform width throughout 

 their course and much smaller than the ducts of the caudal glands. 



The caudal gland cells form a large mass in the anterior half 

 of the caudal portion and are very conspicuous under the micro- 

 scope even in life and total preparations (fig. 1). The cells are of 

 gigantic size when at the height of their secretory activity and do 

 not show so much inequality in size as the post-testicular glands; 

 one of them measured in cross section 96/^ in diameter and four of 

 them occupied nearly the entire breadth of the body at this part. 

 The contents of these glands are coarsely granular and have no or 

 almost no affinity for haematoxylin or carmin, but take up orange 

 well, and this peculiarity puts them in sharp contrast to the post- 

 testicular glands (fig. 5). The nuclei are small (12//) relatively 

 to the large size of the cells, vesicular and contain each a compara- 

 tively large, spherical chromatin mass. The approximate number 

 of these gland cells may be given as thirty. The ducts, which 

 may be two or three times as wide as those of the post-testicular 

 glands, arise one on either side of the median line and open on 

 the caudal disk by means of numerous canaiicules traversing the 

 cuticle. In the intervals of their activities these gland cells are 

 much smaller, 24/*, and the coarsely granular and vacuolated 

 cytoplasm stains well with haematoxylin. 



The cuticle is quite thick in comparison to the small size of 

 the body. Generally speaking, it is thicker in the hinder than in 

 the front part of the body and on the dorsal than on the ventral 

 side. On the dorsal side just behind the pharynx, it is only 5^ 

 thick or less, while near the caudal disk it is nearly three times as 

 thick or thicker. The cuticle shows numerous fine transverse 

 striations which are especially conspicuous in the caudal region. 



The dermal musculature is well developed and consists of the 

 .typical three layers of the circular, diagonal and longitudinal 



