FISH PAKASITES collected at woods hole. 
303 
In a female measuring 3G mm. in length the oesophagus was 6 nun. in length. 
The anal papillae in a male were made out to have the following arrangement: There are 38 
papillae on each side, 24 preanal and 4 postanal. The postanal papilla: are very small. The posterior 
4 preanal papillae are also very small. These are preceded by 4 of medium size, and these again by 
16 large, prominent papillae. While the number appears to ho the same on the two sides, those on 
right side extend a little farther forward than those on left. The spicules not made out clearly. 
Dimensions in millimeters of alcoholic specimen in acetic acid, side view: 
(1) Of a male; length 29, length of head 0.14, diameter of head 0.14, diameter 5 mm. back of head 
0.26, diameter at middle of body length 0.66, diameter 5 mm. from posterior end 0.77, diameter at anal 
aperture 0.14, length of tail 0.07. 
(2) Of a female; length 42, length of head 0.22, diameter of head 0.22, diameter 5 mm. hack of 
head 0.46, diameter at middle of body length 0.95, diameter 5 mm. from the posterior end 1.5; diameter 
at anal aperture 0.33, length of tail, 0.35. 
Acanthoclieilus nidifex sp. nov. 
[Plate 43, figs. 110-11!), TJ. S. N. M. 0534.] 
On August 11 and 19, large nematodes, with minute, inconspicuous jaws, were found in the 
stomach-wall of the tiger shark ( Galeocerdo tigrinus), which appear to belong to an undescribed 
species. The body tapers from a short distance in front of the middle to the anterior end, while it is 
of nearly uniform size from the middle to near the posterior end, plump and smooth, the cuticle 
crossed by faint transverse striaj. Head minute, threc-lobed. Since in some cases three small lobes 
could he seen distinctly, while in others the tliree-lobed character of the mouth is not so plainly 
shown, it would appear that the worm has the power of retracting these oral lobes. Two minute 
conical papilla:, with their points directed forward, could be made out on one of the lobes of a small 
specimen. A large specimen, when viewed from the ventral side in acetic acid, showed two papilla: 
plainly on each of tho lateral lobes. The aperture of the mouth is very minute and is turned a little 
toward the ventral side. The tail is rather slender conical, and about equals in length the diameter 
of body at anal aperture. Lips of anal aperture in large females rather prominently rounded. 
The anal papilla} were not made out with entire satisfaction. A specimen was prepared in the 
following way: After staining, tho dorsal portion of the posterior end was cut away and the ventral 
portion spread out on a slide, ventral side uppermost, and mounted in balsam. In someway the post- 
anal part was lost, so that only tho preanal papilla} are shown. These are arranged in a double row 
on each side of the median line. On the left side the arrangement is regular, and eight pairs, or sixteen 
single papillae, were counted. On the right side, while about the same number of papilla: were counted, 
they were not arranged so regularly as on the left side. They were, however, in two rows, as on tho left 
side. The walls of the intestine are much folded, especially toward the posterior end . A branch of the 
intestine extends forward from tho base of the (Esophagus and lies beside that organ. The thickness 
of the cuticle is about 0.05 mm. Tho ova, with which the uterus of tho specimen sectioned was 
crowded, were 0.04 mm. in diameter, with a transparent, non-staining envelope, surrounding a granular 
mass which stains strongly in alum carmine; tho diameter of this mass is about 0.028 mm. 
Dimensions of a large female (alcoholic) in millimeters: Length 125, diameter of head 0.21, 
greatest diameter of body 2.5, diameter at anus 0.78, length of tail, 0.78. In another of the same 
length the diameter in front of the anus was 0.57 and the length of the tail 0.64. In a small specimen, 
also a female, 35 mm. in length, the length of tho oesophagus was 4 mm. 
These worms occur in crypts or nests, for the most part in the submucosa of the stomach. In 
the lot collected August 11 they were first noticed as hard cyst-like places in the stomach wall. 
When these wore cut into tho worms were liberated. Thoro appeared to be a male and female, at 
least a large and a small worm, together in most cases. Two of tho crypts were lined with a continua- 
tion of the stomach epithelium, which had apparently closed over the point of entrance from tho 
interior of the stomach. In one case the worms lay between the two muscular coats of the stomach 
wall. One small specimen was free in the stomach, and one large one was found along with the 
viscera, but since the head of the shark had been cut off before I examined it for entozoa, these 
nematodes may have beon liberated by the decapitation, tho plane of which passed through the anterior 
end of the stomach. Tho specimens were not inclosed in cysts of connective tissue. 
In the shark examined on August 19 my attention was attracted to these worms by noticing in 
the mucous membrane of the stomach, which had been carefully washed, that there were a few nema- 
