( 37 ) 



NOTICES OF NEW BOOKS. 



Text-book of Embryology. Vol. i. Invertebrata. By E. W. 

 MacBride, M.A., D.Sc, F.R.S. Edited by Walter Heape, 

 M.A., P.R.S. London : Macmillan & Co. 1914. 



This monumental work, of course, specially appeals to the 

 expert laboratory zoologist, the subject demanding for the most 

 part special training and acquaintance with the technique of 

 section-making, &c. This technique is fully dealt with in the 

 course of the work, and directions are also given for the rearing 

 of various free-swimming embryos, which in some cases has 

 been remarkably successful ; a suitable food for some of these 

 minute marine organisms has, it seems, been discovered in the 

 diatom Nitschia, which has been successfully submitted to 

 artificial cultivation. 



Naturally most of the work is not of a character to appeal in 

 this way to the bionomical as well as the morphological zoologist; 

 but it is worth noting that Professor MacBride's style is ad- 

 mirably lucid and avoids technicality even in a highly technical 

 subject. He speaks, for instance, of certain ova as " yolky," 

 where the average niorphologist would have yielded to the 

 temptation of saying " polylecithal." In matters where 

 difference of opinion exists he always puts his arguments 

 temperately ; and in fact the book is a model of exposition. 



Certain types in each natural group are selected for descrip- 

 tion in development, preference being given to those which are 

 accessible to students in temperate regions, and to those which 

 have been most recently worked out. The Echinodermata, on 

 which so much important embryological work has been done, 

 naturally bulk largely in the work, and some of the results of 

 the experimental embryology practised on the ova of the animals 

 of this phylum are of extraordinary interest. Hybrids, for 

 instance, have been produced freely between the sea-urchins 

 Echinus escidentus and E. miliaris, and the hybrids thus obtained, 



