1898J SOME NEW BOOKS 273 



most active sensibility, and the slightest mechanical or chemical 

 stimulus causes an instantaneous change on them. Moreover, the 

 interior of living protoplasm is in a constant state of assuming local 

 differentiations which are as ephemeral and transitory as the move- 

 ments of the outer edge. The authoress insists, with reason, that 

 not sufficient attention has been paid to the changes that killing and 

 staining agents must produce upon so sensitive a mass. They must 

 act first as drugs, however rapid their action may be, and the pre- 

 parations of microscopists may be chiefly pathological conditions. 



We hope that Mrs Andrews may be induced to publish figures 

 of a number of the interesting observations that she has made. If 

 structure can be described, it is possible to figure it, and much that is 

 at present obscure in her text might become of great use to other 

 workers. A sentence from the 'conclusion' will explain shortly 

 the general attitude of the authoress to protoplasm. " The facts 

 seem to warrant present belief that the living substance of all 

 organisms is one physiologically continuous, living, plasma, homo- 

 geneous throughout in its living powers and properties, but having 

 varied local and temporary habits of self-expression, which are largely 

 and inextricably correlated with physical and chemical conditionings 

 of its form and composition as complex emulsive foam — yet not to be 

 wholly identified with or explained hj these." 



Allies of the Woems 



Trait]5 de Zoologie CoNCEi:TE, V. Les Vermidiens. By Y. Delage and E. Herouard. 

 8vo, pp. xii. 372 and 46 coloured plates. Paris : Schleicher Freres, 1897. Price 25 

 francs. 



We welcome this volume of the " Zoologie Concrete," which, although 

 the second to appear, is really the fifth of the great work undertaken 

 by Messrs Delage and Herouard. Tlie first volume was published 

 last year, and reviewed in Natural Science, p. 200, vol. xi. Under 

 the title of " Les Vermidiens " the authors now deal with a number of 

 interesting groups of Invertebrata, at one time or another considered 

 to be more or less closely related to the Annelids. 



First of all the Gephyrea are described, then the Bryozoa. Flwronis, 

 Hhahdopleura, and Cephalodiscus follow, forming a new class, the 

 Axobranchia. The Eotifera and Gastrotricha come next as the class 

 Trochelmia ; the isolated genus Echinoderes is placed in a separate 

 class, the Kinorhynchia. Finally, we have the Ohaetognatha and 

 Brachiopoda. 



We need not again discuss in detail the very original plan adopted 

 in describing these forms — it is essentially the same as in the previous 

 volume. After the anatomy, physiology, and development of the 

 theoretical " type morphologique " of each class has been given, and 

 the types of the subclasses, orders, etc., have been as far as necessary 

 similarly treated, a description accompanied by figures is given of the 

 chief characters of every known genus. Some idea of the complete- 

 ness of the work may be gathered from the fact that the whole 

 volume contains nearly 400 pages, illustrated by 523 figures in the 

 text, and 46 coloured plates. The Eotifers alone occupy some 40 

 pages, 10 plates, and 60 figures in the text. 



Near the end of the volume are general discussions on the 



