CESTODE AND NEMATODE PARASITES. 79 



The head consists of four bothridia, each borne on a short stout stalk. Each 

 bothridium consists of a simple bag-like sucker or depression, the walls of which are 

 rather crinkled and marked with lines, and the edges which surround the opening of 

 the depression are distinctly puckered. All these four bothridia are in both our 

 specimens very much flattened, and all lie in the same flat plain ; the head, in fact, looks 

 like a pressed flower. As far as we know, the animals had never been compressed in 

 any way, and this flatness may be natural to the species. Each sucker measures 

 3 millims. across at its broadest, and the whole head measures 6 millims. from side to 

 side. 



It is followed by a neck which extends some 5 millims. or 6 millims., and then the 

 body becomes segmented. The proglottides are always broader than long, arid the 

 body is broad throughout, differing in that respect from A. cornucopia, VAN BEN.,* 

 whose body " est extraordinairement fin et effile en avant." Anteriorly there is a 

 curious wrinkling at the edges, and the exact correspondence of this with the limits 

 of the proglottides was not made out. The strands of muscles which run down the 

 body in this region are also very conspicuous and easy to see. 



Diagnosis of Anthobotlirium rugosum : 



This species is distinguished from the A. cornucopia, VAN BEN., and the A. musteli, 

 VAN BEN., by the wrinkling of the bothridium and the shape of the body, and from 

 the A. elegantissimum of LONNBERG,! by the absence of a myzorhynchus. Its most 

 striking characteristics are the crumpled suckers, the stout neck, and the longitudinal 

 muscles. Length, when alive, 1 foot. 



Habitat :- The intestine of Trygon walga. 



Echeneibothrium minimum, VAN BENEDEN.| Plate V., figs. 93 and 94. 



This species is in all probability the Echeneibothrium minimum of VAN BENEDEN, 

 although instead of the bothridia fading at their lower end into a stalk like the leaflet 

 of a rose, they are borne on the stalk in a peltate mariner. As in E. var labile, and 

 unlike E. gracile, where there is a terminal areola at each end of the bothridia, the 

 areolas in this species are paired throughout. There is no myzorhynchus. There are 

 thirteen pairs of areolas in each sucker. The bothridium is fringed by a transparent, 

 extensible membranous edge. An excretory tubule runs underneath it. The stalks 

 are very muscular and very mobile. 



The worms are slender but long, larger than those which as a rule live in 

 Elasmobranchs, and are intermediate in length between E. variabile, with its 

 100 millims., and E. minimum, with its 15 millims. to 17 millims. Our species 

 ranged from about 60 millims. to 30 millims. It attains at the maximum a breadth 

 of 1 millim., and this maximum is not necessarily at the posterior end of the animal. 



* 'Mem. Ac. Belgique/ xxv., 1850. 

 t 'Bih. Svenska Ak.,' xiv., 1888-9. 

 I 'Mem, Soc. Belgique,' xxv., 1850, p. 11 4. 



