[93] NOTES ON ENTOZOA OP MARINE FISHES. 811 



at base in one case about .03 mm . The cirrus bulb in this instance small, 

 nearly circular in outline, and .6 mm in diameter. In one instance the cir- 

 rus was protruded about .044'" and measured .023 mm in diameter. No 

 spines were visible on the everted cirrus. In the posterior segments 

 the ovaries occupy about the posterior fourth, and under moderate en- 

 largement appear as finely granular organs, somewhat two lobed, but 

 confluent at the middle line. In segments which precede the extreme 

 posterior ones the ovaries occupy as much as the posterior third, their 

 anterior edge making a line transverse to the axis of the segment. The 

 inner termination of the vagina is in a bulbous enlargement seminal 

 receptacle between the lobes of the ovary. A wide duct or sinus, the 

 uterus, occupies the median line of the segment from the ovary almost 

 to the anterior end of the segment. The vagina leaves the uterus 

 opposite the genital aperture and proceeds directly to the margin of 

 the segment, thus making a right angle with the axis of the segment. 

 The vas defereus is represented by a cluster of tubes at the ant rior 

 end of the segment. The remainder of the interior of these segments is 

 filled with large, spherical, granular bodies, which I take to be the testes. 

 In the mature free proglottides the anatomy is quite different from what 

 has been given for the posterior segments. In the former an inner ob- 

 long space, the uterus, which is of considerable extent, becomes converted 

 into an ovisac which is filled with small ova. Such a proglottis when 

 rendered transparent in glycerine resembles a double sac. The tissue 

 of the outer sac appears homogeneous, with the exception of a few small 

 granular masses, which apparently represent the remnants of the testos 

 and vas deferens. The inner sac is sharply defined from the outer by 

 a thin limiting membrane and is filled with ova. 



The foregoing points in the anatomy of the segments were confirmed 

 by thin sections, and a few additional facts obtained. In longitudinal 

 sections the cirrus was seen to be armed with minute spines throughout 

 its entire length. Both the cirrus and its bulb are remarkably small in 

 proportion to the size of the mature proglottis. The vagina was seen to 

 open immediately in front of the cirrus. The vas defereus was found to bo 

 quite voluminous, and appeared in sections as convoluted vessels filled 

 with a dense, filamentous substance, which I take to be spermatozoa. 

 Some of the large, granular bodies already mentioned, were seen, in sec- 

 tions, to contain, besides the granular nuclei, abundant fibrous tissue. I 

 have interpreted this as indicating the transformation of the nuclear con- 

 tents of the testicles into spermatozoa. In some sections in which the 

 uterus appeared as a broad median sinus with irregular outlines the 

 vagina was seen to lie, not in the median sinus, but along one of its 

 sides, within the dense, granular tissue which form the boundary walls 

 of the sinus. This was about the middle of the segment. In some sec- 

 tions, however, which showed the posterior part of the segment, the va- 

 gina was seen as a convoluted tube between the lobes of the ovary, and 

 appeared for a short time after leaving the ovary to lie in the median 

 sinus. 



