42 PROCEEDINGS OF THE NATIONAL MUSEUM vol.88 



of the uterus extend from the space between the testes to the posterior 

 end, passing dorsal to the left border of the ventral sucker and 

 beside the cirrus pouch to the genital pore. The vitelline glands lie 

 between the intestinal rami and the lateral margins of the body and 

 extend from the level of the testes, or a little ways in front of them, 

 nearly to the posterior end. In some cases they are continuous; in 

 others they are broken up into follicles. In most cases that were 

 observed there were six follicles on the right side and seven on the 

 left. The excretory vessels under some conditions are conspicuous, 

 appearing as rather large lateral vessels, which begin at the level 

 of the oral sucker, or in some cases at the level of the pharynx, and 

 extend to the posterior end, where they unite in a short excretory 

 vessel with thick, muscular walls. The ova have rather thick shells, 

 and are about 0.04 by 0.02 mm, in size. 



Longitudinal and diagonal muscle fibers are strongly developed in 

 the neck. A conspicuous feature of sections of this distome is a 

 layer of deeply-staining subcuticular cells. 



Found very commonly, but in small numbers in each host, in the 

 puffers of the Woods Hole region, usually in the pharyngeal cavity. 



Hosts. — Oldwife {Balistes vetula)^ puffer {Sphoeroides maculatus). 



Record of collections. — From oldwife : Five, collected by Vinal N. 

 Edwards, September 8, 1903. Ground color in formalin greenish, 

 reddish chocolate where intestines showed through the body wall; 

 plump, neck folded ventrally. Measurements, made on a series of 

 cross sections of a strongly contracted specimen: Length, 2.5 mm.; 

 breadth, 1.35 mm.; vertical diameter, 1.12 mm.; oral sucker, length, 

 0.23 mm., breadth, 0.42 mm. ; pharynx, length, 0.14 mm., breadth, 0.21 

 mm.; ventral sucker, length, 0.77 mm., breadth, 0.84 mm.; ova 0.045 

 by 0.024 mm., with thickish shells, not collapsed. 



From puffer: Collection of June 26, 1903, consisted of four vials 

 containing 69 distomes from puffer, many of them in clusters adher- 

 ing to each other by the ventral suckers. One hundred fishes examined 

 by Vinal N. Edwards. 



Eleven, collected by Vinal N. Edwards, July 11, 1903, "from 

 throat" of puffer. Twenty, collected July 9, 1904, from pharynx of 

 one puffer ; very active, necks very extensible, becoming linear ; tend- 

 ency to adhere to each other by the ventral suckers ; prevailing color 

 blood-red in larger specimens, pale yellow in smaller worms, when 

 flattened and viewed with transmitted light. One, collected by Vinal 

 N. Edwards, September 12, 1904, "from gills" of puffer. Two, col- 

 lected by Dr. Irving I. Field, July 8, 1905, "from body cavity" of 

 puffer. 



Two, collected August 6, 1906, from near opening of pharyngeal 

 sack of puffer. General ground color in life pale red or flesh-color; 



