Hevie/cs — Lankcsfer's Treatise on Zoology. 233 



such statements like those on p, 257 re the supposed relationships 

 of the Molluscoidea to the Mollusca, and the supposed total 

 absence of all hard parts in Tunicata, are apt to mislead the 

 student, unless he has had a very thorough zoological training. 

 So also would some of the definitions of the classes and orders 

 of the Mollusca. 



Studying a work of this description one cannot help wondering 

 whether specialists in different groups will ever come to any 

 agreement as to the differences which constitute species, genera, 

 and families, and in this connection we think that the student who 

 voluntarily takes up the study of the fossil Cephalopoda will be 

 a bold man indeed. 



We must congratulate Dr. Eastman and his collaborators on the 

 excellent results which have attended their efforts, and we think 

 that Professor von Zittel was wise in allowing his work to bo 

 expanded and altered to its present form, which Messrs. Macmillan 

 have put before us in such excellent condition. All English- 

 speaking students of Palaeontology will rejoice at its appearance. 



III. — A Treatise on Zoology. Edited by E. Ray Lankester. 

 Part III : The Echinoderma. By F. A. Bather, M.A., assisted 

 by J. W. Gregory, D.Sc, and E. S. Goodrich, M.A. pp. vi 

 and 3-14:, with 308 figures in the text. (London : Adam & 

 Charles Black, 1900.) 



AT last we have actually before us the first instalment of Professor 

 Lankester's long promised Treatise on Zoology. It is some- 

 what unfortunate that the appearance of this part has been so long 

 delayed (for we notice that the MS. of some parts of the work were 

 completed rather more than three years ago), since, as we all know, 

 zoological text-books have a way of getting out of date very rapidly, 

 owing to the enormous amount of work which is being done all 

 over the world. 



Professor Lankester promises us nine more parts of this work, 

 which are to be written as far as possible by graduates of Oxford 

 University. We only hope that these parts will make a fairly early 

 appearance, since, judging from the present part, they should be of 

 immense service both to the palaeontologist and to the student 

 of living forms. 



The present work deals with the Echinoderma, and since the 

 greater part of it is written by two pala;ontologists it will probably 

 appeal more strongly to the readers of this Magazine than some 

 of the parts which have yet to appear. The ordinary zoologists 

 will be apt to consider that the palceontological side is perhaps 

 a little overdone ; but when we remember that the phylum Echino- 

 derma includes the Pelmatozoa, three classes of which are extinct, 

 and the remaining class, the Crinoidea, consists mainly of fossil 

 forms, the preponderance of the palseontological aspect becomes at 

 once accounted for. This group occupies 179 pages and is the main 



