1913-] Records of the Indian Museum. 231 



and triturated under a cover-slip till the tissues have been disin- 

 tegrated ; but when a number of specimens of different sizes are 

 to be compared together, I have found it more convenient to 

 mount them whole under simple pressure, after the preliminary 

 treatment with potash. As boiling with potash rapidly disinte- 

 grates the animal and usually results in the loss of the penis, the 

 plan adopted has been to pour boiling 5%. caustic potash solution 

 on to the specimens, which then ia a few minutes become clear 

 without falling to pieces. 



Has well has pointed out that in several species of Temnoce- 

 phala two distinct regions can be recognized in the penis (1887, 

 p. 296). This is so in T. semperi as has already been noticed by 

 Semper (1872, pi. xxiii, fig. 7) and Weber (1890, pi, i, fig. ij. 

 In the proximal region the chitin is smooth, whereas in the distal 

 region or glans it is armed internally with fine, close-set spines 

 (fig. 6). In the smallest specimens of T. semperi that I have seen, 

 the proximal region is very little longer than the distal (fig. 7), but 

 as the animal grows the former becomes more rapidly enlarged than 

 the latter, so that in approximately full-grown specimens the 

 chitinous lining comes to have the form shown in fig, 5. Finally, 

 in a few specimens from the Dawna Hills, all of them full-grown, 

 the whole organ has become very much longer and slenderer, as 

 is shown in fig. 4. 



TemnocepJiala semperi lays its eggs on the sides of the femora, 

 and occasionally on the abdominal terga and the sides of the 

 carapace, of its host. They are very like those of T. fasciata 

 figured by Haswell (1887, pi. xxii, fig. r8). They vary greatly 

 in size, being from about o*5-i*o mm. in length, and two or 

 three times as long as broad. They are covered with a hard 

 brown shell, from a little towards one end of which arises a thin 

 (? chitinous) thread, that is commonly broken during the preserva- 

 tion of the specimens. The animal appears to develop inside the 

 egg with its tentacles bent along the body as in T. madagascari- 

 ensis (Vayssiere, 1891, pi. i, fig. 6). 



Although Temnocephala semperi is the only species of its 

 group of which adults were obtained in the course of the Abor 

 Expedition, there is some evidence that another occurs at the base 

 of the Abor Hills. Dr. Annandale, while examining specimens 

 of a race of the Atyid prawn Caridina weberi from the Assam- 

 Bhutan frontier, noticed in their gill-chambers eggs in every 

 respect similar to those of the peculiar little Temnocephaloid 

 recently described by him as Caridinicola indica (1912). In one 

 egg the shell had been ruptured and a young Caridinicola was 

 protruding from it. In the gill-chamber of a specimen of the 

 same prawn taken at Dibrugarh by Mr. Kemp, Dr. Annandale 

 found other eggs which differed in their smaller size and in being 

 apparently devoid of a coloured shell. It is therefore probable 

 that Caridinicola or an allied animal lives on Atyid prawns that 

 inhabit the streams of north-eastern Assam. 



