Pavel leoeaN We CH SO DRS) HomeO vir laine) Dan 
om Gow cls dasy 
By JAMES HORNELL. 
(Plates ix—x.) 
IL—PROSTHECOBOTHRIUM UROGYMNI, n. sp. 
II.—BALANOBOTHRIUM TENAX, n. gen. et sp. 
III. TETRARHYNCHUS ANNANDALEI, n. sp. 
(1), PROSTHECOBOTHRIUM UROGYMNI, nl. sp. 
(Pl. ix, figs. r—3). 
Two specimens of this fine cestode were obtained from the 
spiral valve of a male Urogymnus asperrimus (Bl. Schn.), trawled 
in 9 fathoms on the north end of the Periya Par, one of the Ceylon 
Pearl Banks in the Gulf of Manaar, February 1908. 
When alive the larger of the two measured 25 cm. in length, 
shortening to 14cm. at death. The species is closely related to 
P. dujardinii (van Beneden), differing therefrom chiefly in its much 
greater size, the great elongation of the neck and the superior 
development of the suctorial loculi of the bothridia. 
The scolex is furnished with four elongated sessile bothridia. 
Each is sub-lanceolate in outline, divided into three distinct loculi 
by two transverse muscular coste. The most anterior loculus is 
considerably the longer being equal to the combined length of the 
two posterior ones. In life the mobile edges of the bothrium 
curve inwards ard all three loculi are distinctly seen as deep 
sucker-like cavities; in this latter characteristic the present species 
exhibits a marked divergence from Diesing’s type of the genus 
where the bothridia are described as undivided, each having a 
suctorial appendage at its posterior extremity. Johnston’s des- 
cription of the same species (P. dujardiniz) necessitates a modifi- 
cation of the original generic diagnosis as he describes each 
bothrium as ‘‘ really divided into three loculi by two transverse 
curved coste,’’ adding, however, that the most anterior loculus 
“is not apparently concave.’’ The distal portion of each bothrium 
possesses a tongue-like mobility enabling it to twist and turn in 
search of a new holding when the living worm is dislodged from 
its attachment within the host’s intestine. The tips of the 
bothridia may then be seen projecting prominently and at a 
considerable angle from the neck. 
