58 Papers from the Marine Biological Laboratory at Tortugas. 



Host, Teuthis hepatus: 

 1908, July II, I fish, I distome. 



Dimensions, life: Length 0.86; breadth 0.44; oral sucker 0.22; 

 pharynx 0.09; ventral sucker 0.29; ova 0.031 by 0.017. 



Dictysarca virens gen. et sp. nov. (Figs, 130-136.) 



Etymology: otKroo^, network; t«/'-?, flesh. 



Body variable, pyriform, fusiform, or ovate when at rest, rather thick, 

 translucent greenish. So far as observed the body appears to be char- 

 acteristically reticulated, especially when viewed with transmitted light ; 

 ventral sucker 1.33 to 1.5 times the diameter of the oral; neck approxi- 

 mately 0.25 the entire length ; pharynx adjacent to oral sucker; esophagus 

 short or none; intestinal rami, inflated in some cases, extend to the pos- 

 terior end. Genital aperture median, ventral, a short distance behind 

 mouth; cirrus very short, prostatic portion vertical, cells small, tube 

 relatively large, continuing in a seminal vesicle dorsal to the ventral 

 sucker. Testes 2, lateral, opposite, a short distance back of the ventral 

 sucker, ovary towards the posterior end, dorsal ; shell-gland and seminal 

 receptacle ventral to ovary; vitelline glands 2, lobed, in front of ovary. 

 Folds of the uterus voluminous, mainly dorsal, from near the posterior 

 border of the ventral sucker to near the posterior end; ova small. The 

 metraterm is ventral to the seminal vesicle, turns sharply ventrad just 

 behind the prostate, and runs parallel to the caudal border of the pros- 

 tate to open with it into the common genital duct. 



The excretory vessels appear to unite above the oral sucker. They 

 approach each other a short distance back of the ventral sucker. At 

 first they are ventral to the intestines, behind the ventral sucker they 

 become median, later they are variable. Thus in the vicinity of the 

 yolk-glands the intestinal rami are close together and the excretory 

 vessels are lateral to them. Near the posterior end they unite into a 

 single larger vessel which opens at the posterior end. The excretory 

 pore is surrounded by numerous nucleated cells. 



In sections the intestines are seen to be about midway in a dorso- 

 ventral direction. The yolk-glands are ventral and nearly symmetri- 

 cally placed on either side of the median line. The shell-gland is between 

 them and about on the same level. On the right margin, at about the 

 posterior third and for some distance back, the folds of the uterus contain 

 copious spermatozoa mingled with the ova. In all of my specimens the 

 parenchyma is characteristically areolar, as shown in figs. 133 and 134. 

 Among the specimens which I have studied there are individuals in which 

 only rudiments of the genital organs appear. In them as well as in the 

 larger specimens there is the same loose, areolar structure of the paren- 

 chyma. There is, however, a larger proportion of structureless material 

 in the loose framework of tissue in the smaller specimens than in the 

 larger. One of the small distomes when sectioned showed rudiments of 

 an ovary, but little more that could be distinguished with certainty. 



