[11] ENTOZOA OF MARINE FISHES OF NEW ENGLAND. 463 
terminal papilla or auxiliary acetabulum. The neck, or unjointed part 
of the body, is short. In some the transverse striw, 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 living specimens as 
much as in those which have been preserved in alcohol. “The most usual 
shape for the mature segments to assume is subquadrangular, 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 
if 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 I, 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. 
