[11] ENTOZOA OF MARINE FISHES OF NEW ENGLAND. 463 



terminal papilla or auxiliary acetabulum. The neck, or uujoiuted part 

 of the body, is short. Iu some the transverse striae, which indicate the 

 beginning of segments, were discernible almost immediately back of the 

 head. The first segments are usually crowded, broader than long; 

 subsequently they increase in length and become considerably longer ; 

 than broad. In some of the ultimate segments the length is four or 

 five times that of the breadth. The shape of the mature and nearly 

 mature proglottides is very various. 



This irregularity of shape is to be found in the liviug specimens as 

 much as in those which have been preserved in alcohol. The most usual 

 shape for the mature segments to assume is subquadraugular, some- 

 what contracted about the posterior third in the vicinity of the genital 

 openings, expanding in front of this ; the anterior end contracted into 

 a short constricted neck where it joins the preceding segment. Some- 

 times this constriction occurs at the posterior instead of the anterior 

 end of the segment. The ovaries are two sets of radiating tubes situ- 

 ated in the posterior end of the segment. The anterior half of the ma- 

 ture segments is crowded with globular masses (testes). These masses 

 fill at least the anterior two-thirds of the adolescent segments. In the 

 mature segments of all the specimens I have yet examined the center 

 is filled with a convoluted mass, consisting of the retracted penis and 

 the vas deferens, with perhaps the vagina and a portion of the oviduct. 

 The extremely long and convoluted vas deferens is found protruding 

 from the ruptured side of some of the segments which have been pre- 

 served in alcohol. This worm is remarkable for the slight change which 

 it experiences when preserved in alcohol. Even the extremely delicate 

 leaf-like folds of the bothria were not observed to curl up or shrivel 

 when subjected to moderately strong alcohol. Fig. 15, Plate II, is a 

 sketch made of a living specimen. I have since mounted the same in- 

 dividuals for permanent preservation. In the various processes of dehy- 

 drating with alcohol, staining with eosin, rendering transparent with 

 oil of cloves, and afterwards mounting in Canada balsam, there has not 

 been any shrinking or change of form, at least to any appreciable ex- 

 tent. 



The water- vascular system is plainly indicated by two rather large 

 tubes, which in the neck and anterior part of the body are sinuous, and 

 each situated about as far from the other as it is from the nearest edge 

 of the strobile. In subsequent segments they become widely separated 

 from each other on account of the interposed ova and genital organs. 



The substance of the head and pedicels of the bothria is for the most 

 part fibrous tissue. The conical portion of the head is thus sharply 

 marked off from the so-called neck. While the former is made up 

 largely of fibrous tissue, the latter is granular, with but few longitudi- 

 nal fibers. This feature can be easily brought out in preserved speci- 

 mens by simple staining. 



