626 Revieics — Professor Lankester's Zoology. 



This volume is about equally divided between the Porifera and 

 the Ccelenterata, a division which appears to us to be somewhat 

 unfair, for the components of the latter group differ so much more 

 from one another than do the various classes of the Porifera, that 

 in our opinion they should have been allotted a larger space. At 

 the same time we should not like this to have been done at the 

 expense of Professor Minchin's article, which appears to be a most 

 admirable one, and one that will long serve as a valuable intro- 

 duction to the study of the Porifera. This article contains a large 

 amount of original observations and many new figures, but so great 

 is Professor Minchin's modesty that only those who have worked 

 at sponges will recognize the new matter. In dealing with the 

 histology we are glad to see that Professor Minchin throws con- 

 ;siderable doubt upon the special sense-organs and nerve-cells as 

 described by Stewart, Sollas, and von Lendenfeld, and we could 

 only wish that Mr. Fowler, in dealing with the so-called ganglionic 

 cells of the last-mentioned observer in the Hydroids, had been 

 ■equally bold. 



The gi-eat difficulty in these composite textbooks is to mete out 

 equal treatment to the various groups of animals dealt with, as 

 €ach writer has his own ideas on the style of article required, and 

 we are afraid that both the articles on the Hydromedusse and the 

 Anthozoa suffer somewhat from a comparison with that on the 

 Porifera. Those on the Hydromedusse and the Scyphomedusas 

 especially appear to be far too condensed and hardly critical 

 enough for this ambitious work ; the illustrations of these parts, 

 too, are for the most part very antiquated. 



Perhaps the part which appeals most nearly to the palaeontologist 

 will be that dealing with the Anthozoa by Mr. Bourne. Here, 

 at any rate, no fault can be found with the age of the illustrations, 

 almost all of which appear to have been specially drawn for the 

 article. Unfortunately, owing to the adoption of the half-tone 

 process, the printing of these beautiful figures has not been always 

 successful, Mr, Bourne's article obviously suffers from delayed 

 publication, and consequently much important work dealing with 

 the formation and nature of the coral- skeleton has to be briefly 

 referred to in an appendix. Mr. Bourne has done considerable 

 work on the relation of the hard and soft parts in the corals, but 

 we cannot help asking for his authority in his representation of 

 the epitheca in fig. 28 as a saucer-like structure surrounding the 

 theca but separated by a distinct interval into which a hollow 

 reduplication of the body-wall extends. 



The present volume contains six chapters, which, with the 

 exception of chapters iv and v, are separately paginated, and the 

 contained figures are separately numbered ; each, further, is pro- 

 vided with an index : these indices are sometimes difficult to 

 find, and we personally should have preferred a continuous 

 pagination and a general index at the end of the volume. 



