78 CEYLON PEARL OYSTER REPORT. 



The head is squarish, and yet sab-globular, with four minute suckers equidistant 

 from one another at the angles. The suckers are borne on a kind of cup-like external 

 bowl, which surrounds a central portion, and between this cup-like shield and the 

 central portion a number of simple tentacles protrude. 



These tentacles are very curious, and, as far as we know, are unique amongst the 

 Cestoda. They are finger-like processes, with no branching, and they hang over the 

 central portion of the head. They seem to be about sixteen to twenty in number, 

 but in the preserved specimens it was impossible to count them accurately. 



In the living specimens a number of concretions, apparently of a calcareous nature, 

 occurred at the base of the head, just where it joins the neck. The neck is long, no 

 trace of stabilization appearing for at least a distance of half a centimetre behind the 

 head. The proglottides, when they do appear, are shown by lines in the centre of the 

 body, which do not at first reach the side, so that for a time the sides of the worm are 

 unindented, straight, and almost parallel ; then the dividing lines reach the edge and 

 the sides of each proglottis bow out, and by the time the proglottides are about as 

 long as they are broad the body has a somewhat moniliform appearance. The 

 proglottis is symmetrical, about a line which passes across it midway between its 

 anterior and posterior edge ; there is no overlapping and no trace of it. The posterior 

 proglottides are flask-shaped, and seem to be little more than bags of eggs. The 

 reproductive pores are very irregularly alternate, some six or seven being to the right, 

 then one or two to the left, then seven or eight to the right, and so on. The penis 

 was often protruded. 



Habitat : The intestine of Trygon uarnak. 



TRYGON WALGA, MULLER and HENLE. 



The Tamil name is " Manal tirikkai," signifying " Sand Ray." This species is 

 perhaps the commonest Ray taken by fishermen in the neighbourhood of the pearl 

 banks. A considerable number were examined, as follows : 



A. Caught on the N.W. Cheval Paar, April 4, 1904. 



B, C, U, E, and F. Caught in fishermen's nets in the open sea, January, 1905, off 

 Dutch Bay Spit, N.W. Province, Ceylon. 



G. Taken on a line on the North Modragam Paar pearl banks, February 2, 1905. 



Food. As shown by stomach contents, this Ray lives chiefly upon small crusta- 

 ceans, supplemented frequently by octopods, gephyreans, polychjetes, and occasionally 

 thin-shelled small molluscs. 



Anthobothrium rugosum, n. sp. Plate V., fig. 92. 



Two specimens of the worm were taken from the intestine of a Trygon walga. 

 One measured 65 millims. when preserved, but it had stretched to 12 inches when 

 alive, the other 20 millims. in length. The greatest breadth of the body is about 

 2 millims. 



