80 CEYLON PEARL OYSTER REPORT. 



The bodv has, in fact, a somewhat lumpy, untidy appearance, and is thrown in 

 irregular wrinkles and sometimes knots. There is no neck, as in E. gracile* The 

 posterior segments are not very long, at most twice or three times as long as wide. 

 The genital pore is lateral. 



This species came from the intestine ot Trygon walga, the same specimen which 

 contained T. herdmani. 



Echeneibothrium simplex, n. sp. Plate VI., figs. 95, 96 and 97. 



The species is one of the simplest of the genus to which it belongs. Its head 

 consists of four stalked bothridia, each shaped like a violet leaf. The edge of each is 

 divided by horizontal ridges into areolas, some twenty-two in number. It was difficult 

 to make out the exact number. There is no myzorhynchus. The body measured 

 2 centims. in length. There is also no neck, the transverse divisions beginning 

 immediately behind the head. The number of segments is about 100. They are 

 nearly all broader than long, except the last six or seven ; the anterior three of these 

 are about square, the others are longer than broad, the last being perhaps twice as 

 long as broad. The reproductive pores are lateral and alternate ; there are often two 

 on the same side, followed by two on the other. 



The diagnosis of Echeneibothrium simplex is : 



Very simple leaf-like bothridia, with areolas, some twenty-two stretching right 

 round the edge of each bothridium. No neck. Genital pores rather irregularly 

 alternate. 



Habitat : Intestine of Trygon walga. 



Echeneibothrium trifidmn, n. sp. Plate VI., figs. 98 and 99. 



This beautiful little Cestode was taken from the spiral intestine ot Trygon, walga, 

 where it lived with a Tylocephalum uarnah. There were only three examples, 

 which differed a little in length, but averaged 6 millims. or 7 millims. The head bears 

 four leaf-like bothridia, stalked and very mobile. The basal or posterior half of each 

 bothridium is single, and carries nine transversely elongated areolas. The proximal 

 end of each bothridium is, however, split into two halves, and each half bears nine 

 areolas, of a somewhat rounded form. There are thus altogether twenty-seven areolas, 

 nine large and eighteen small, in each bothridium. A fine, delicate, extensile 

 membrane edges the bothridium. These bothridia are borne on stalks which can be 

 readily elongated and contracted, as the sketch indicates. The unsplit part is usually 

 curled with the split part into a C. There is no myzorhynchus. The proglottides 

 at an early stage show traces of the testes, but only the posterior half show any 

 genital pores. These are lateral, and very irregularly alternate. 



Diagnosis of Echeneibothrium trifidum: 



This species is characterised by its trifid bothridia with twenty-seven areolas. 



Habitat: The intestine of Trygon walga. 



* Zschokke, ' Mem. Instit. Nat. Gencv.,' xvii., 18S9. 



