Helminth Fauna of the Dry Tortugas. 69 



triangular, with the pointed end directed caudad. The ovary lies on the 

 anterior border of the testis. It is oval, its longer diameter transverse, 

 and it is much smaller than the testis. The seminal receptacle lies on the 

 left side, extending from the ovary along the margin to a point a little 

 behind the level of the posterior edge of the ventral sucker. The folds 

 of the uterus lie behind the ventral sucker and between that organ and 

 the ovary. The ova are large and not numerous. 



Host, Tylosurus marinus: July 9, 1906, 1 fish, 2 distomes. 



Dimensions of larger specimen, life, moderately compressed: Length 

 1.96; breadth, anterior 0.22, middle 0.66, posterior 0.11; oral sucker 

 0.21; pharynx, length 0.12, breadth 0.09; ventral sucker, length 0.40, 

 breadth 0.35; ova 0.071 by 0.054. Length of smaller specimen 1.50. 



The body was smooth, but with a few small nodular papillae at the 

 anterior end. 



Deradena obtusa gen. et sp. nov. (Figs. 160, 161.) 



The specimens here figured and described may belong to different 

 species. They are in poor condition and but little of the anatomy could 

 be made out. Body smooth, fusiform, tapering to each end, but rather 

 more posteriorly than anteriorly. The rami of the intestine extend to the 

 posterior end. The pharynx is adjacent to the oral sucker; ventral 

 sucker larger than oral. Genital aperture between the suckers but nearer 

 oral than ventral. Ovary and seminal vesicle at caudal border of ventral 

 sucker. Testis one, conspicuous, occupying a large part of the space 

 behind the ventral sucker. The vitellaria are diffuse, posterior, and mar- 

 ginal, and extend forward in front of the ventral sucker. In front of the 

 ventral sucker there are lateral clusters of large, nucleated cells, which 

 are interpreted as yolk- forming glands, as in the preceding species. The 

 ova are few and large and lie dorsal to the ventral sucker. In the 

 specimen figured from T. cceruleus they lie for the most part behind the 

 ventral sucker. 



Host, Teuthis hepatus: 



1907, July 1, 1 fish, 3 distomes; July n, 1 fish, 1 distome. 



Dimensions, life: Length 1.22; breadth 0.50; oral sucker 0.19; 

 pharynx 0.07; ventral sucker 0.24; ova 0.075 by 0.051. 



Host, Teuthis cceruleus: July 6, 1908, 1 fish, 2 distomes. 



Dimensions, life: Length 0.98; breadth 0.29; ventral sucker 0.16; 

 ova 0.075 by 0.051. 



MONOSTOMIDiE. 



Barisomum erubescens gen. et sp. nov. (Figs. 173-183.) 

 Etymology: /&*/>£?, a boat; ow/ia, body. 



Body smooth, convex dorsally, both transversely and longitudinally, 

 and concave both transversely and longitudinally on the ventral surface. 

 Viewed from the ventral side the body is boat-shape. The ground-color 

 in life is pink; the excretory vessels usually, and the intestines often, 

 filled with black, granular material. Oral sucker circular in outline, 

 subterminal. A cross-section of the body behind the oral sucker is more 

 or less circular, as is also a section made near the posterior end. In all 



