230 F. H. GraveIvY: Temnocephalidae. [Vol. VIII, 



Sukli, eastern side of hills, ca. 2100 ft., 22 — 29- 



XI-II. 



Below Sukli, ca. 1500 ft. 



The habits of Temnocephala semperi seem to be very like 

 those of other species of the genus. M}^ observations on Burmese 

 specimens were very hurried, but, so far as the}^ go, they confirm 

 Mr. Kemp's on Abor ones. The following account is based on 

 these. 



The creatures are extremely contractile and their great acti- 

 vit}^ is most striking — indeed it is apt to be startling the first 

 time living specimens are seen. They live, often in large numbers, 

 on the lower surface of the body and among the basal joints 

 of the legs of their host, which is apparently always a crab of 

 the genus Potamon, and of the subgenus Potamon or Geotelphusa. 

 Temnocephala has not so far been found on specimens of Potainis- 

 cus, the only other subgenus of Potamon found in India, possibly 

 on account of the fact that the members of this subgenus are 

 less aquatic in their habits. When the animal is quiescent, its 

 median tentacle is extended directly forwards, the intermediate 

 tentacles are elevated, and the posterior ones are depressed. As 

 a rule the last-named tentacles do not assist in progression but 

 remain outstretched and curved slightly forwards, while the tips 

 of the other three are applied to the ground. The bod}^ is then 

 hunched up and pressed forwards till these three tentacles lie entirely 

 beneath it, after which the posterior sucker lets go its hold to find 

 a new one further forwards ; then the same process is repeated. 



When separated from its host, T. semperi stands and waves its 

 tentacles around, as though trying to perceive a new one, or crawls 

 rapidly about. Occasionally, when it is greatly irritated, the 

 tentacles are doubled back and tucked away beneath the concave 

 ventral surface of the body. 



Haswell (1888, p. 283) found that the food of Australian 

 Temnocephalidae consisted of small Crustacea and insect larvae. 

 In the specimens examined from the Dawna Hills, remains of the 

 latter are abundant, of the former very rare. The Abor specimens 

 do not throw much light on the nature of the food, but one 

 contains a lot of diatoms and other matter, so arranged as to leave 

 little doubt that they were introduced in the gut of some other 

 animal, perhaps an aquatic Oligochaet 



The animal as a whole is white and semi-translucent in life, 

 with the stomach showing through as a yellowish patch a little 

 behind the single pair of small black eyes. I have nothing to add 

 to our present knowledge of the general anatomy of the animal, 

 though I can confirm from sections the results of both Weber's 

 and Merton's investigations of the species ; but the chitinous lining 

 of the penis appears, on account of its special importance in 

 taxonomy, to be worthy of greater attention than has been 

 bestowed upon it in any paper I have yet seen. 



This cuticle is most readily examined in detail after the 

 animal has been treated with hot caustic potash and then crushed 



