282 Records of the Indian Museum. [Vol. XIII, 



The scope of this paper is to record the results of the investi- 

 gations commenced with a view to discover the nature of the sub- 

 stance which produces this interesting phenomenon, which has also 

 been observed in fishes, and further to trace the relation of it to 

 the other histological elements. Incidentally, reference will be 

 made to the colouring matter of other tadpoles, chiefly Indian 

 forms known to me, — in all those particulars in which the}^ ap- 

 proach the general scheme of pigmentation occurring in the two 

 species of Microhyla which form the subject of this paper. The 

 literature referring to this section of the paper is given below in a 

 foot-note.' 



The head of the tadpole of M. ornaia, which is nearly two- 

 thirds of the size of the body, is perfectly transparent, but this is 

 not so in M. mhra. Behind the eyes, in the former species, there 

 is a characteristic diamond-shaped black mark just above the cra- 

 nium. Usually a yellow line runs fore and aft of this mark behind 

 which is a glandular area. Over the vertebral column is the char- 

 acteristic golden streak which may also extend in front over 

 the diamond-shaped mark already referred to. Sometimes the 

 lungs show through the transparent skin on either side of the verte- 

 bral band ; more often, however, the skin may be yellowish green. 

 The sides and ventral surface of the abdomen glitter with silvery 

 brightness, while the throat is colourless. The ventral lobe of the 

 tail is more or less pale copper coloured. When the dorsal metallic 

 streak is absent, due to absorption, the underlying black band can 

 then be seen. 



The other Engystomatid larvae known to me are uninteresting 

 in regard to their colouration. The tadpole of one species of 

 Kaloula {K. triangularis) is absolutely transparent without any 

 colour markings except on the head; and another {K. variegatn) 

 has a transparent head, but the body and tail are blotched, be- 

 sides two blue spots in the region of the groin The tadpoles of 

 K.pulchra, K. obscura, and Cacopus systoma are densely pigmented. 



The points of interest that call for remark, in regard to the 

 colouration of the larvae of the Ranid family, are the occurrence 

 of bright orange red in the posterior third of the tail in 

 R. breviceps and Rhacophorus maculatus ,^ which as metamorphosis 



1 For an account of the colouration of Indian tadpoles the follow ing literature, 

 though not complete, may be consulted : — 



Annandale, Rec. hid. Mits., VIII, p. 21 (1912). 



Boulenger, Aim. Mus. Genova, (2) V', p. 420 1 iSSy-^SS); Proc. Zool. Soc. 

 London, 1893, pp. 526-527. 



hlower, Proc. Zool. Soc. London, 1S96, p. 911 and 1899, pp. 892, 902. 



Anderson, Proc. Zool. Soc. London, 1S95, p. 66c. 



Butler, Joiirn Bombay Nat. Hist. Soc, XV, pp. 193, 387 (1903-04). 



Ferguson, Joiirn. Bombay Nat. Hist. Soc, XV, p. 499 (1903-04). 



Narayan Rao, Rec Ind. Mits.. X, p. 265 (1914) ; XI, pp. 31, 349 (1915). 



Boulenger, Proc. Zool. Soc London, 1891, pp. 606-607, mentions the occur- 

 rence of metallic dots in the larvae oi Rana arvalis and R. temporaria. 



^ Flower, in his account of the tadpole of the Malay race of this species, de- 

 scribes the colour as pinkish {Proc. Zool. Soc London, 1896, p. 906). 



