CESTODE AND NEMATODE PARASITES. 71 



ones ; they soon, however, narrow, and only very slowly widen again. The sides 

 of the proglottides are straight and almost parallel, and although they project very 

 slightly at their hinder end they do not overlap the succeeding segment. The 

 posterior proglottides are almost three times as long as they are broad, and instead 

 of having square ends they have rounded ones and are swollen in the middle. Their 

 contents seems to be a roomy uterus with numerous large ova. In the stained 

 specimens the central region of each proglottis stains deeply, making a deep line 

 along the centre of the body. The reproductive pores are alternate. 



The diagnosis of Phyllobothrium blakei is : 



Small delicate forms, 1 centim. long. Head with four frilled bothridia, practically 

 sessile. No neck ; the proglottides which come after the head are broader than those 

 that follow. No overlapping at the posterior end of each proglottis. Ends of posterior 

 proglottides rounded. Genital pores alternate. 



Habitat : Intestine of Trygon kuhli. 



Rhinebothrium ceylonicum, n. sp. Plate V., figs. 74 and 75. 



Although the stalks or pedicels of the bothridia (if indeed they exist at all) must 

 be very short, the specimens about to be described seem to us to belong to LINTON'S 

 genus Rhinebothrium.* The head bears four fleshy bothridia at the four angles, 

 back to back. Each bothridium is divided into two halves, as in Rh. flexile, LINTON, 

 by a longitudinal groove, and each half bears a number of horizontal slit-like areolas 

 placed transversely. The number of these areolas was not exactly made out, but 

 it is somewhere about twenty. The whole recalls a rasp (/atVq), after which the creature 

 takes its name. In the preserved specimens, of which only two were taken, the head 

 was rather broader than it was long, its greatest breadth being 4 millims. Judging 

 from the figure taken of the head whilst alive, the length about equalled the 

 breadth. In the living form also the bothridia seem more clearly distinct from one 

 another and from the head ; in the preserved form they have all shrunk together. 



The length of the body of our longer preserved specimen is 5 centims., but, as in 

 both, the tail is curved up in the lateral plane, and perhaps, if uncoiled, the length 

 would be 5 '8 centims. or 6 centims. When alive, it measured 9 inches. The body 

 is stout and wide. Our second specimen also giving off mature proglottides was 

 a little more than half this size. In the middle, which is the widest portion, it is 

 3 millims. broad, and it tapers away slightly both in front and behind. It is 2 millims. 

 thick and is very stiff and firm in the preserved condition. 



The neck is short, and the proglottides are at first very narrow from front 

 to back. There seems to be a curious false strobilization whereby five or six 

 segments are grouped together, but this may have been an individual character. 

 The posterior angle of each proglottis was salient and projected slightly over the 



* 'United States Commission of Fish and Fisheries,' Report of the Commissioner for 1887, part xv. ; 

 p. 768. Washington, 1891. 



