[143] NOTES ON ENTOZOA OF MARINE FISHES. 861 



They consist of an outer layer of fine muscular fibers crossing the lon- 

 gitudinal fibers of an inner layer at right angles. Beneath this there is 

 a fine granular layer, with a few longitudinal fibers. Some of the gran- 

 ules of this layer are distinctly nucleated. In sections of some of the seg- 

 ments there is a layer of longitudinal muscles in which the fibers are 

 arranged in rather thick parallel fascicles. The interior of the imma- 

 ture segments is, in great part, filled with the oval or elliptical sper- 

 matic capsules, .03 to .06 nim in diameter, and containing granular cells, 

 some of which are nucleated, from .025 to .005"' m in diameter. 



Sections of ripe segments show the entire segment to be filled with 

 ova, with the excep'.ion of a small space in the center, which is occu- 

 pied by the remnant of the ovary, and one of the anterior corners into 

 which the cirrus bulb is crowded. The ova are yellowish in color, with 

 unstained granular contents, measuring about ,014 mm in diameter, and 

 for the most part with an extremely irregularly collapsed membranous 

 shell. Some ova were found near the margin in which the shells were 

 entire, and were then seen to be very thin and delicate and separated 

 by a clear space from the granular interior. These measured from 

 028 mm to .038 mm in diameter, and the granular contents .022 mm in diam- 

 eter. 



The ova occur in these segments in enormous numbers. They fill 

 the segment to its extreme outer margins. The division between the 

 mass of ova of two adjacent segments was found to be reduced to a thin 

 partition .008 mm thick. The marginal walls of the segments were re- 

 duced to about the same thickness. 



SYNDESMOBOTHRIUM Diesing. 







This genus is characterized by Diesiug as follows : Body articulate 

 tseniajform ; neck tubular, rounded at the base ; head tetragonal, with 

 four terminal prominent bothria attached to head by posterior margin, 

 cruciformly disposed, oval, slightly convex, joined with each other at 

 the base by a membrane ; proboscides four, filiform, armed, each one 

 running through a bothrium (pedicel) exctirrent at apex, long, re- 

 tractile in the neck. Genital apertures marginal ('?). In intestines of 

 marine fishes of tropical America. 



Syndesmobothrium filicolle, sp nov. 

 [Plate xv. Figs. 2-4. J 



A single specimen belonging to the genus Syndesmobothrium, without 

 mature segment, the neck attached to a linear oblong body (blastocyst) 

 and with the proboscides retracted was found in the spiral valve of a 

 sting ray (Trygon centrura) in August, 1884, at Wood's Holl, Massachu- 

 setts. 



This description is necessarily so meager that I have hesitated to 

 bestow a specific name on the specimen which furnishes the data for it. 



