524 THE ZOOLOGIST. 



years, when this period will be alike termed the Victorian age and 

 the Darwinian era, how will he be associated with this great 

 conception ? Was Huxley the Baptist or the Paul to Dar- 

 winism ? In the light of these volumes we consider him both. 



A Treatise on Zoology. Edited by E. Ray Lankester, M.A., 

 LL.D., F.R.S., &c. Part II. The Porifera and Coelentera, 

 by E. A. Minchin, M.A., G. Herbert Fowler, B.A., 

 Ph.D., and Gilbert C. Bourne, M.A. With an Intro- 

 duction by E. Ray Lankester. Adam & Charles Black. 

 The second volume has now appeared of this advanced well- 

 named ' Treatise.' Vol. III., which appeared first, has already 

 been noticed in these pages, and the present volume very fully 

 maintains the excellence of the Oxford publication. 



The Editor contributes an introduction on a subject of great 

 biological importance, viz, the coelom, a name proposed by 

 Haeckel for the cavity in Vertebrate animals often called the 

 " pleuroperitoneal cavity." This is a branch of technical biology 

 of the profoundest interest, but one necessarily little discussed 

 in our bionomic pages. This " introduction " can, however, be 

 consulted as the last word in the investigation to date, and, as its 

 writer has proposed, it is " the vindication of the coelom as a 

 morphological factor of primary importance in the animal series, 

 and the maintenance of the conclusion that the ccelom by its 

 presence justifies the separation of a higher grade of Enterozoa, 

 the Ccelomoccela, from a lower grade, the Enteroccela, in which it 

 is not differentiated as a separate cavity." 



Prof. Minchin has written very fully on the Sponges. These 

 creatures afford their evolutionary evidence, as do all other 

 animals. " Many deep-sea sponges, especially those of the 

 order Monaxonida, are to be regarded as having migrated down- 

 wards from the shore-line in comparatively recent times, and in 

 such forms the influence of life in still water is seen in a great 

 regularity of growth, resulting in the development of a secondary 

 symmetry." The colours of Sponges are very varied, and often 

 very bright; but Prof. Minchin states that green is a rare colour 

 among marine Sponges, though it is the usual tint of the fresh- 

 water Spong Mince, where, however, it is due to chlorophyll. 



