502 Bibliographical Notice. 
on this group, but I believe it forms one of the best generic 
characters of Palpomyia. It occurs in all the species of the 
genus which I have examined (including those of Heteromyia, 
which, in my opinion, is not properly separable from Palpo- 
myia), but not in the allied genera Johannsenomyta and 
Hartomyva. 
BIBLIOGRAPHICAL NOTICE. 
The Evolution of Aquatic Reptiles. 
Many attempts during recent years have been made to set before 
the layman the evidences of Evolution in language devoid of 
technical terms. Some of these efforts have at the same time 
resulted in volumes which have proved most acceptable to the 
trained zoologist. Prof. Williston’s book on ‘ Water Reptiles Past 
and Present’ (‘The University of Chicago Press and the Cambridge 
University Press, London) is one of these. 
The author writes with a very intimate knowledge of his subject, 
gleaned not merely from specimens in museums, but also from work 
in the field. Hence he writes with an almost deadly accuracy—so 
that, apart from eccentricities of spelling and grammar, which 
grate on English ears, the critic finds little to cavil at. But here 
and there we seem to catch him tripping. ‘Thus, in describing the 
method by which the crocodile drowns its prey, we are told that, 
by reason of the extremely backward position of the posterior nares, 
the animal is enabled to “‘ breathe with the mouth,” while the 
extremity of the snout, carrying the external nares, is thrust above 
the water. Perhaps he merely meant to say that, by reason of the 
backward migration of the nares, the animal is able to breathe even 
while the mouth is filled with water. Again, itis scarcely accurate 
to describe the tortoises as animals which have developed ‘‘ the 
strange habit of concealing themselves inside of their ribs.” 
The Ichthyosaurs naturally are described at length in this 
volume, but, curiously, no mention is made, in describing the 
paddles, of the posterior fin-like membrane, with its supporting 
rays, recalling the fin-rays of fishes. 
These, however, are but small blemishes in a book brimful of 
interest and profusely illustrated. 
