Helminth Fauna of the Dry Tortugas. 73 



especially at the distal ends. Genital aperture ventral, median, at 

 bifurcation of intestines, surrounded by a muscular disk with abundant, 

 deeply staining nuclei. The cirrus-pouch is oval and contains the pyri- 

 form cirrus and a few coils of the seminal vesicle. The prostate gland is 

 not conspicuous and is represented apparently only by the not numerous 

 cells in the cirrus-pouch. Testes 2, more or less lobed, situated about 

 the middle of the body, one following the other and close to it, slightly 

 diagonally placed. Vas deferens very long, in a coiled mass behind and 

 ventral to "the cirrus-pouch. Ovary small, subglobular, usually median 

 and near the posterior end. Shell-gland at caudal border of ovary and 

 between it and the anterior border of the posterior sucker. In one speci- 

 men both ovary and shell-gland were to the left of the median line, and 

 those folds of the uterus which were immediately in front of the posterior 

 sucker contained spermatozoa. The vitelline glands are represented 

 by lateral clusters of irregularly rounded masses, somewhat variable in 

 extent, but usually extending from a little in front of the posterior sucker 

 to a point on a level with the middle of the posterior testis. The uterus 

 extends from the shell-gland at the posterior end of the body to the coiled 

 vas deferens, and the metraterm continues ventrad of the cirrus-pouch 

 to open beside it at the common genital opening. The ova are relatively 

 large and oval. The lateral excretory vessels unite above the esophagus 

 just back of the mouth-pharynx, pass ventrad of the intestinal rami, and 

 unite at the anterior border of the posterior sucker. The single excretory 

 vessel now passes to the dorsal side of the posterior sucker, but the excre- 

 tory pore was not seen. A light-gray non-staining mass above the mouth- 

 pharynx and another smaller one below were noted, faintly indicated in 

 fig. 202 dh, rh. They suggest nerve masses, but no cells were demonstrated 

 in them. With the exception of these fine, granular, non-staining masses 

 the parenchyma of the body consists of a loose network of fibers. The 

 body-wall is rather weak, the cuticle, circular and longitudinal muscle 

 layers each rather thin. Peripheral gland-cells few and scattering. 



Dimensions in balsam : Length 3.78; breadth, anterior 0.14, middle 

 0.71, posterior 0.86; anterior sucker, length 0.14, breadth o.ii ; posterior 

 sucker, length 0.51, breadth 0.65. Dimensions of a smaller specimen: 

 Length 1.60; breadth, anterior 0.14, middle 0.77, posterior 0.67; anterior 

 sucker, length 0.14, breadth o.ii : posterior sucker, length 0.30, breadth 

 0.39. Ova in each 0.075 ^Y 0-034. 



Host, Pomocanthus arcnatus: 



1906, July 18, I fish, numerous trematodes. 



1907, July 3, I fish, ID trematodes; July 11, i fish, 43 trematodes; 

 July 15, I fish, I trematode. 



1908, June 29, I fish, 60 trematodes; July i, i fish, 18 trematodes; 

 July 3, 2 fish, 65 trematodes; July 4, 2 fish, 190 trematodes; 

 July 5, 2 fish, 13 trematodes; July 7, 2 fish, 52 trematodes in 

 larger and i in smaller fish. 



Dimensions, life: Length 1.65; breadth, anterior 0.21, middle 0.32, 

 posterior 0.35; oral sucker, length 0.15, breadth 0.14; posterior sucker, 

 length 0.46, breadth 0.30; ova 0.078 iDy 0.040. The length in general 

 varied from 1.5 to 3.5. 



