576 
Cestodes from Selachians 
The hook is 0-12 mm. long measured along the curved surface and 
0-03 in diameter at the base. Each bothridium is divided into three 
loculi by two transverse costae, the anterior loculus is largest, the 
posterior two sub-equal. Anterior to the hooks each bothridium is 
surmounted by a triangular pad with a single accessory sucker upon it. 
Posteriorly the bothridium is separated from the neck and sHghtly 
turned outward. 
Neck slender, 1-2 x 0*1 mm. anteriorly immediately behind the 
head. Strobila generally delicate. The neck is followed by quadrate 
segments, 0-1 x 0-16 mm., which increase in size posteriorly, the 
length increasing more rapidly than the breadth, so that the last 
segments are much elongated, the terminal segment measuring 1*0— 
1-4 X 0-25 mm. In the posterior segments the genital openings are 
indicated by slight elevations which are readily seen at the posterior half 
of the lateral margin of each segment; they are irregularly alternate. 
Linton recently obtained this species from the spiral valve of 
Mustelus canis at Woods Holl; my specimens are identical with those 
Linton described, differing only in the dimensions of various parts: 
Head 
Bothrid. 
Bothrid. 
Hook 
Neck 
Neck 
Last 
segment 
Last 
length 
length 
breadth 
length 
length 
breadth 
length 
segment 
Linton 
0-9 
0-6—0-64 
0-34 
0-20—0-24 
— 
0-2—0-24 
10 
0-32—0-6 
Mihi 
0-5 
0-44 
015 
0-12 
1-2 
01 
10—1-4 
0-24 
The above table shows that Linton’s specimens are as a rule larger 
(measurements in mm.). 
7. Galliobothrium verticillatum (Rud., 1819) van Beneden, 1850. 
Syn. Bothriocephalus verticillatus Rudolphi, 1819. 
Onchohothrium verticillatum Rud. of Diesing, 1850. 
Acanthobothrium verticillatum (Rud., 1819) van Beneden, 1849. 
Tetrabothrium verticillatum (Rud.) Wagener, 1854. 
This species is very common in the spiral valve of Cynias manazo 
(Bleeker) in Japan. My specimens were obtained on several occasions 
at Tokyo, and other parts of Japan, and were generally foimd associated 
with other cestodes. In May, 1913, numerous specimens were collected 
at Nakatsu. They were much larger than any specimens previously 
collected at either Tokyo or Hiroshima, all measuring about 140 mm. 
in length. The external characters and internal structures of my 
