1899.] BATEAOHIAXS OP THE MALAY PEKINSTJIA AND SIAM. 903 



lower crest deeper than the upper. The mouth has neither hard 

 beak, labial teeth, or papillse, but consists of a simple upper lip and 

 a contractile lower one. 



Colour. In life these tadpoles are transparent and almost 

 colourless. The eyes and viscera are therefore very noticeable. 

 But there are a number of minute yellowish-brown spots, parti- 

 cularly on the back, where they form a somewhat diamond-shaped 

 figure, and on the muscular poi'tion of the tail. 



Size. Length of body 7 mm. ; width of body 4 mm.; length of 

 tail 13 mm. ; depth of tail 3 mm. 



The recently transformed young measure about 7'5 mm. from 

 snout to vent. 



A remarkable feature of these tadpoles is that the hind feet are 

 for a time completely webbed, the web is very fine and colourless ; 

 when the young frogs leave the water this web disappears. 



N.B. — At various times I have found in Penang some very 

 remarkable tadpoles (Plate LX. figs. 2, 2a-2c), the affinities of 

 which could not be conjectured, till, haviug made out the tadpole 

 of MicroJiyla ornata, there seems no doubt they belong to some 

 Engystomatoid Batrachian. Although the species they develop 

 into is still unknown, I think it desirable to describe the tadpole 

 in this paper. The first tadpoles with the spiracnlum thus 

 placed, and with this simple mouth, that I came across, I caught in 

 Singapore early in 1896. At the time I imagined them to belong 

 to Callula pulchra (and still do so), but was unable to prove it ; 

 on later occasions I have found these " transparent tadpoles " 

 in Bangkok (where I was able to observe them grow into 

 M. ornata), in the Dong Phya Pai, in Kedah, and on Penang 

 Hill, all of which I have no doubt are of the genus Microhyla. 

 These " transparent tadpoles " (of which I have observed four or 

 five different species), besides differing in structure, differ entirely 

 in habits from the tadpoles of the Kanidse and Bufonidse. Instead 

 of passing a great deal of their time on the bottom, they are usually 

 just under the surface of the water, continually opening and 

 shutting their mouths ; they are very delicate, and difficult to 

 transport alive in a bottle even for a few miles. 



Bescription of " Transparent Tad2Joles," Penang 

 (Nov. and Dec. 1896). 



Form. The length of the body is about Ij its width ; the length 

 of the tail is from 1^ to 1| the length of the body. 



JSvsti-ils. Distance of nostrils apart 1-4 mm. ; distance from 

 nostril to end of snoiit 2-5 mm. ; distance from nostril to eye 

 4 mm. 



The nostrils are placed close together on the upper surface of 

 the head, and are nearer the end of the snout than the eye. The 

 distance to the eye is from Ig to 1| the distance to the end of the 

 snout. The distance between the nostrils is about ^ the distance 

 between the eyes. 



