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Zoology ot tbc 3n\>ertebrata. 



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* ' ^T^HE last few years have witnessed a great extension in our 

 1 knowledge of the structure and relationship of the Inver- 

 tebrata. The earth has been ransacked for new forms, 

 and improvements in microscopes and in technique have facili- 

 tated a more minute and thorough examination of these forms in 

 the laboratory. This increase in our knowledge has necessarily 

 been accompanied by a re-arrangement of material ; many inter- 

 mediate forms have been discovered, and unexpected relationships 

 have been revealed, and these have entailed a revised classifica- 

 tion." 



In the handsome volume before us Mr. Shipley has given such 

 an account of the Invertebrata as cannot fail to be most helpful 

 to the student. He describes in a very careful manner, at least, 

 one or more examples of the larger groups, and gives, generally, a 

 shorter account of the most interesting modifications presented 

 by other members of the group. He treats his subject more 

 particularly from a morphological standpoint, touching but lightly 

 on the Histology, Embryology, and Natural History of the forms 

 described. 



The author states in the Introduction that " the organic world 

 has developed in two diverging directions, one corresponding to 

 the animal and the other to the vegetable kingdom, and though 

 there is no difficulty in distinguishing the higher forms of these 

 two kingdoms, it is often by no meams an easy matter to deter- 

 mine whether some of the lower forms should be grouped with 

 the plants or with the animals ; hence any scheme of classification 

 is dependent on individual opinion. There are a number of 

 characters which, if met with in an organism, would justify us in 

 classing it as an animal ; but in many cases one or more of these 

 animal features are absent, and, again, other features may be 



* "Zoology of the Invertebrata ; A Text-Book for Students." By 

 Arthur E. vShipley, M.A., Fellow and Assistant Tutor of Christ's Coll., and 

 Demonstrator of Comparative Anatomy in the University of Cambridge. 

 8vo, pp. viii — 458. (London : Adam and Charles Black. 1S93). Price 1 8s. 



net. 



