100 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 2 



follicles are closely grouped, about twenty-seven on each side, imme- 

 diately ventral to the ceca, extending forward from the anterior bor- 

 der of the ovary, for about four lengths of the ovary. The uterus is 

 highly coiled, especially in the anterior region. It extends, between 

 the ceca, from the ovary to the level of the genital pore. The an- 

 terior portion of the uterus enters a moderately developed metra- 

 term with thick glandular walls and a narrow internal layer of longi- 

 tudinal muscles (fig. 10). The metraterm lies to the left of the cirrus 

 sac, and tapers to the genital pore. The eggs measure 19 to 23 by 

 9 to 11 /i., with a single long filament at each pole. The filaments are 

 about 83 to 106 jx in length. 



The excretory pore is at the extreme posterior end of the worm, 

 and is surrounded by muscles. The excretory vesicle is unusual. It is 

 very large and voluminous, filling at least the posterior fifth of the 

 body (fig. 9). It has thick glandular, highly folded walls. The vesicle 

 divides just posterior to the terminals of the ceca. In all specimens 

 the right limb was greatly enlarged in the region of the division. 

 The limbs pass anteriorly, dorsal to the ceca as irregular, unbranched, 

 narrow tubes which unite dorsal to the oral sucker. Each limb twists 

 upon itself to form a complete circle at the level of the sucker before 

 uniting with the other limb. 



GENERIC DIAGNOSIS OF CETIOSACCUS 



Elongate Teloporiinae. Body smooth, collar weak, anterior ven- 

 tral depression present. Both ends of body rounded. Ceca simple. 

 Genital pore median, one fourth body length from anterior end. 

 Testes round or oval, smooth, intercecal, median and tandem, in 

 posterior half of body. Seminal vesicle coiled, entirely anterior to 

 mid-body, just posterior to cirrus sac, with anterior prostatic por- 

 tion. Cirrus papilla-like In terminal chamber. Ovary spherical me- 

 dian, pretesticular. Shell gland large. Seminal receptacle absent. 

 Laurer's canal present. Uterus Intercecal, preovarian. Eggs with 

 single polar filament at each pole. Excretory vesicle voluminous, 

 walls highly folded, in posterior fifth or more of body, limbs simple 

 and uniting anteriorly. From intestine of marine iguana, Ambly- 

 rhynchus cristatus. Type species: C. galapagensis . 



