270 DR. MALCOLM SMITH ON 



Dimeusions. Very variable ; well grown individuals are : — total 

 length, 40 ; head and body, 12 ; depth of tail, 6 mm. 



The j'oung on leaving the water are very variable in colour ; 

 greenish, grej^ish or brownish, sometimes with regular markings upon 

 the back. The large metatarsal tubercle is fully developed, and tiie 

 lower jaw is thickened, but the peculiar truncate formation of tiie 

 snout takes some weeks to develop. 



In general characters, and in its peculiar translucency of 

 colouration, this tadpole closely resembles certain of the Microhi/la 

 larvae, and except for its narrower and longer tail, is practically 

 indistinguishable from them. Tn life, however, it may be easii}' re- 

 cognised by the peculiar position which it assumes in the water. It 

 has the same habit of "' floating" quietly about just below the surface, 

 but whereas all the Microlnjla tadpoles that I know of lie in a 

 horizontal position, Gli/phoiilossus molossus assumes an oblique one. 

 The obliquity may not be great, but in fully grown individuals it is 

 often very marked, and 1 have seen them almost perpendicular. 

 Usuallj' they lie at about an angle of 45° with the surface of the water. 



Like the Microlii/la larvae also, they are sociable, and are 

 generally to be seen in shoals. Some of these assemblies are very 

 large, and must be composed of many thousands of individuals, all 

 closely packed together with their heads turned in tlie same direction. 



The spawn is laid is masses, and floats on the surface of the 



water. Breeding commences at Ta Rua and Nong Pling at the end of 



May or in June, as soon in fact as thei-e is sufficient water to permit of 



it. As the ponds in these localities are entirely dry from about 



November to May, they obviously cannot spawn there during those 



months, and I was somewhat surprised, therefore, to have larvae sent 



me from Koh Lak in February, whore the rainfall is practically the 

 game. 



Calluella guttulata (Blyth). 



E.xcept that it grows to a larger size, and apjiears to have the 

 ti)) of its tail always black, the tad})ole of tliis species is indistinguisli- 

 able from that of Glyiihofjlossm inolossus ; and I have always found 

 them together, in the same ponds and at the same time of the year. 

 They assume the same oblique position in the water. 



JOfK.\. N.\T. UIST, SOC, SUM 



