[59] NOTES ON ENTOZOA OF MARINE FISHES. 777 



terior part of the body on account of the convex margins of the seg- 

 ments. In the other specimen the margins of the segments are not 

 convex. The latter specimen is not so long as the other and the pos- 

 terior segments do not correspond in their degree of development. 



The water vascular system was plainly visible in the living specimens 

 as rather large sinuous vessels lying a little way from each margin. 



The segments are rather thick and crossed by very fine transverse 

 lines, so that the margins of the segments when sufficiently magnified 

 are finely crenulate. The posterior end of the last segment in one of 

 the specimens was concave and appeared to have a fluted border. 

 These last two features are doubtless due to the superficial layer of cir- 

 cular and the deeper layer of longitudinal muscles. The body, from 

 the constriction which separates it from the neck, to the posterior seg- 

 ments, was, in life, very contractile, and was constantly shortening and 

 elongating itself. 



The genital apertures are marginal and situated about the middle 

 of the segment. The vagina opens immediately in front of the cirrus. 

 The two organs have a common external cloaca. Ova were observed 

 escaping from the middle of a margin of one segment and from the an- 

 terior edge of another, in a specimen which was somewhat flattened 

 under a compressor. Each ovum consisted of a hyaline envelope in- 

 closing a granular mass. The dimensions of these living ova are: 

 diameter of outer hyaline envelope .0279 mm ; diameter of inner granular 

 part .0203 m »'. 



In the alcoholic specimens these ova have undergone considerable 

 modification. The hyaline envelope has, in most cases, collapsed and 

 adheres to the granular interior as a closely investing membrane. This 

 investing membrane has in most cases a very irregular outline. It has 

 the appearance of sending out radial prolongations which are often as 

 long as the diameter of the granular mass. In a very few cases the 

 hyaline envelope is but little contracted. The diameters of the ova, 

 with collapsed investing membrane, vary from .008 to .014 mm . The 

 greatest diameter of an ovum with an unbroken envelope was .022" uu , 

 the diameter of its granular contents being ,01G mm . The latter is deeply 

 stained with carmine. These ova are not free but are in a loose cluster 

 which is held together and attached to the segment by fine interlacing 

 hair-like fibers. 



The cirrus is long and slender, and, so far as observed, without spines. 



Anatomy of posterior segments. — Thin sections were made of two seg- 

 ments from near the posterior end of one of the specimens. The cuti- 

 icle at the margins had disappeared in some places, in others it still 

 adhered and presented a brokenly serrate outline. Beneath the cu- 

 ticular layer is a thin coat of fine muscular fibers, consisting of an 

 outer layer of circular and an inner of longitudiual fibers. This is un- 

 derlaid by a coarse granular layer, and this again by a layer of coarse 

 longitudinal fibers. The latter present a very peculiar appearance. 

 They are surrounded by granular tissue, while many of them are char- 



