CURRENT LITERATURE. 



41 



biology, with respect to the mollusca, are very sparse in the few books which 

 deal with the subject, but many cases of protective colouring have been 

 recorded, and although, in the work under consideration, space has been found 

 for a number of these, one cannot help wishing for more. Figure 2S, shewing 

 a supposed case of true mimicry of a Co;n/5 by a Stivinbiis, is reproduced. Para- 

 sitic molluscs, commensalism and variation have their fair share of attention 

 and the facts presented under the last heading should act beneficially on the 

 minds of those who still describe species from trivial shell-characters. 



Passing on through the com- 

 mercial aspects of the subject 

 and the uses to which shells 

 are put by civilized and un- 

 civilized man, the mollusca are 

 considered structurally and 

 physiologically in an exceed- 

 ingly thorough manner. Per- 

 haps the chapter on digestive 

 organs might be singled out 

 for greater praise, seeing that 

 it contains an exhaustive 

 account of the radula ; while 

 on the other hand, in the 

 chapter on the shell, although 

 the adult form and the stages 

 of its growth (see Figure 172) 



are dealt with in great detail, comparatively little light is thrown upon its 



minute structure. 



Figure 172. Three stages in the growth of 

 Cypraea exanthvma, L. 



Geographical distribution is discussed in the three chapters which follow, 

 and illustrations are given of characteristic mollusca from the various regions 

 and their divisions (see Figure 210). Finally, the several moUuscan classes are 

 systematically considered as fully as is possible in 

 the space which remains ; the classification as 

 stated in the preface being in accordance with the 

 views of " leading recognized specialists." 



It is true that Pelseneer has been followed in so 

 far as he puts the old class Pteropoda under the 

 gasteropod order of Opisthobranchiata, but no further, 

 the forms still being kept together as a sub-order. 

 The Amphineura are included also under Gasteropoda, 

 and are not considered to be worthy of the class- 

 distinction accorded to them by Pelseneer. 



In other instances un-notified, "discrepancies" 

 will be found in which the specialists have been 

 followed incompletely, or not at all. 



It is, of course, easy for one who has taken an 

 interest in some small points in Malacology to 

 disagree with Mr. Cooke's treatment of those points, 

 but the fact remains that the book, as a whole, 

 deserves all praise, if only for two things — in the 

 first place, it is not a monument to the weakness and 

 laziness of authors, the short-sightedness and stingi- 

 ness of publishers, or even to the extinction of 

 draughtsmen and engravers, for the bulk of the 

 illustrations are original ; and in the second case the patriotic way in which, 

 although the labours of workers outside the country are fully recognized, 



Figure 210. CochlostyJa 

 (Chrysalis) tniinlorof-nsix, 

 Brod. Mindoro Phillipines. 



