52 CEYLON PEARL OYSTER REPORT. 



except at the posterior end there is no sign of the cuticle being indented between 

 them. One peculiarity is that the body, usually about the middle of its length, is 

 thrown into coils and twists of a very characteristic form. In the anterior 

 proglottides one sees a central stained part, possibly the uterus ; posteriorly, however, 

 the scattered testes are visible, and the vas deferens and penis, represented sometimes 

 by a clear area, runs from about the centre of the anterior border of each proglottis 

 to the middle of either side, right or left, irregularly alternating. 



The diagnosis of Tetrarhynchus peridercms may run : 



Head with well-marked backwardly directed collar which, together with the head, 

 is dark grey ; the body is white. Some 70 millims. long. The two lappets are 

 almost split into four and lie adpressed and crumpled in the head. Teeth all of the 

 same size. Neck rather long. No constrictions between the proglottides except 

 posteriorly. Penis runs from centre of anterior edge of proglottis to the centre of 

 either side. 



Habitat : The small intestine of Carcharias gangeticus. 



CARCHARIAS MELANOPTERUS, Quoy and Gai.makd. 



This fish is in Sinhalese called " Kunda mora." The specimen we examined 

 contained in its stomach a large specimen of the genus Caranx. It was caught at 

 Dutch Bay Spit on January 5, 1905, and contained in its intestine the three 

 species of Cestodes described immediately below. 



Phyllobothrium minutum, n. sp. Plate III., figs. 32 and 33. 



One or two examples of two forms of Phyllobothrium were found in the intestine 

 of Carcharias melanopterns. They are a great deal smaller than, for instance, 

 Phyllobothrium thridax described by Zschokke, but their head and general structure 

 coincides with that of the genus. 



Phyllobothrium minutum measures 8 millims. in length and at the widest 0"3 millim. 

 in width. The neck is very fine and whip-like ; it terminates in a small head. The 

 head bears four bothridia with on each an accessory sucker or areola (Plate III., 

 fig. 33). The edges of the bothridia are crumpled, at least slightly so. The round 

 areola was near the centre of each bothridium. The neck is long .and very trans- 

 parent. The number of proglottides some 80 to 100 ; each slightly overlaps the one 

 behind it. The central proglottides are still a little broader than they are long, but 

 the posterior are at least one and a half times longer than broad (Plate III., fig. 32). 



The reproductive pores are lateral and all on the same side. 



The diagnosis of Phyllobothrium minutum may run : 



Length 8 millims., greatest breadth 0"03 millim. Head with four sessile bothridia, 

 each bearing a single, large, round areola near the centre. Proglottides 80 to 100, 

 neck fine and transparent. 



Habitat : Carcharias melatioptcrus, in the intestine. 



