for the years 1917-20. xi 



Viviparidae (Plate C). These points are discussed in detail in the volume 

 cited. More recent investigations on the fossil species of Upper Burma, 

 published in Vol. L of the Records of the Geological Survey of India 

 have cast further light on the subject, while the discovery in Manipur 

 that the peculiar sculpture of the shell of certain Viviparidae is con- 

 nected with the persistence of structures on the edge of the mantle 

 present in the embryos of smooth-shelled forms gives promise of 

 interesting results. 



The fish of the Inle Lake are hardly less interesting than the mol- 

 luscs. The endemic species, which are relatively numerous, are re- 

 markable for the small size, brilliant colouration, large eyes and poorly 

 developed tactile organs of the majority — peculiarities correlated with 

 the exceptional clearness of the water. From a morphological and 

 taxonomic point of view the most interesting form is a small eel-like 

 creature which I have called Chaudhuria caudata. This fish I 

 regarded as a primitive Eel, but Mr. Tate Regan of the British Museum 

 has given reasons for accepting it as a degenerate relation of the Masta- 

 cembelid^ or Stickleback Eels, which are not even remotely related 

 to the true Eels but are convergent with them. 



Survey of the Macroscopic Fauna of the lakes of Asia.— Our investi- 

 gation of the Inle Lake forms part of a much wider scheme which I 

 can hardly hope to see brought to a conclusion in my own time. I refer 

 to a survey of the macroscopic fauna of the lakes of Asia the possi- 

 bility of which has been suggested to me by the results of experience. 

 I cannot give a better idea of the extent to which this proposal has 

 been realized in the last three years than by quoting the abstract of a 

 paper read at the Nagpur meeting of the Indian Science Congress held 

 in January last. 



" The author, alone or with other members of the Zoological Survey 

 of India, has in the last seven years investigated the macroscopic fauna 

 of seven Asiatic lakes, namely, Lake Biwa in Japan, the Tai Hu in 

 China, the Tale Sap in Siam, the Inle Lake in Burma, the Chilka Lake in 

 India, the Hamun-i-Helmand in Persia and the Lake of Tiberias in 

 Palestine. The fauna of these lakes is much more diverse in facies and 

 composition than that of lakes in Europe and North America, and no 

 one biological feature of importance has been found common to all 

 of them. They may be separated into four types as follows : — 



(a) Maritime Lakes (the Chilka Lake, the Tale Sap and the Tai 

 Hu), 



(h) Inland River-Basins (the Hamun-i-Helmand), 



(c) Normal Inland Lalies (Lake Biwa and the Lake of Tiberias), 



{d) Specialized Lakes (the Inle Lake). 



{a) Maritime LaJces. 



" The Chilka Lake, the Tale Sap and the Tai Hu represent an in- 

 teresting developmental series both geographically and faunistically, 

 illustrating two important biological phenomena, viz. (i) the way iij 



