S. Yoshida 
575 
and form of segments, etc., are taken together they are sufficient to 
establish the species as new to science. I accordingly name it Acantho- 
hothrium ijimai in honour of the collector of the specimens. 
Diagnosis. Length 40 mm. or more (probably longer than this in 
fully matured form). Head considerably large, provided with 4 sessile 
bothridia, which are arranged in a diagonal position. All bothridia 
turn forward and are united together closely by their anterior half, 
giving a square appearance when seen frontally. The square is placed 
nearly at right angles to the long axis of the head. Each bothridium 
is oval in shape, it measures 1-6—1-7 x 1-2—1-4 mm. and is divided 
into three unequal loculi by two transverse septa, the anterior the 
largest and the posterior the smallest. One pair of bifurcated hooks 
is planted on the proximal border of the anterior loculus of each both¬ 
ridium. The hook is small in size and r-shaped. Three accessory 
suckers occur on the proximal end of each bothridium, one is large and 
occupies an antero-median position, two are smaller and situated 
postero-laterally to the first. 
Neck varies in length between 0-2 and 0-6 mm. according to the 
condition of contraction. The segments gradually increase in breadth, 
reaching a maximum (1-1—1-5 mm. or more) and tapering toward the 
very end; their length increases progressively along the whole length 
of body, attaining a maximum at the last segment, which is longer 
than broad. The genital pores are on the lateral margin and are 
irregularly alternate. 
Host. Dasyatis akaei (Muller and Henle), spiral valve. 
6. Calliobothrium eschrechtii (van Beneden, 1849). 
Syn. Acanthobothrium eschrechtii van Beneden, 1849. 
Onchobothrium (Call.) elegans Diesing, 1854. 
The specimens were obtained from the spiral valve of Cynias manazo 
(Bleeker) in Tokyo, 24. v. 1907; in association with other cestodes 
{Acanthobothrium, Calliobothrium, Rhynchobothrium, Phyllobothriurn and 
Anthobothrium). 
External characters. Length 4—11 mm.; maximum breadth of 
the posterior segments, 0-25 mm. Head provided with four opposite 
bothridia measuring 0-44 x 0-15 mm. Each bothridium armed with 
two pairs of simple, claw-like, w'ell developed, hollow hooks of equal 
size and similar shape; the outer hook of each side is slender and 
sfightly curved while the inner hook is stout and strongly curved. 
