246 Bibliographical Notices. 



dentition of the vole *, 25 per cent, of specimens examined 

 may be abnormal, a fact which, when still larger numbers 

 are available, may yet prove the saving of my subdivision 

 of the hedgehogs. 



In conclusion, I must thank my critic for the exceedingly 

 temperate and forbearing way in which his remarks are 

 couched. Criticisms thus conscientiously formed and fairly 

 expressed cannot surely fail to advance our science. 



BIBLIOGRAPHICAL NOTICES. 



Zoological Results based on Material from New Britain, New Guinea, 

 Loualtij Islands, and elsewhere, collected during the Years 1895, 

 1896, and 1897, by Arthur Willeg, D.Sc. Lond., Hon. MA. 

 Cantab. Part IV. Cambridge, May 1900. 



The long-delayed fourth part of Dr. Willey's ' Zoological Results ' 

 is now before us and proves fully equal, both in interest and in the 

 general excellence of its contents, to its predecessors. It contains ten 

 memoirs, the majority of which are devoted to reports on the collec- 

 tions made by Dr. Willey in various groups of the animal kingdom. 

 Three, however, are on subjects of morphological interest. The first 

 of these is the opening paper of the volume by Mr. J. Stanley 

 Gardiner, " On the Anatomy of a supposed new Species of Coeno- 

 psammia from Lira.'' Mr. Gardiner divides his subject into four 

 heads, dealing respectively with the general anatomy of the skeleton 

 and specific description, the general anatomy of the polyps, minute 

 anatomy, and some conclusions relating to the body-layers in the 

 Actinozoa. He comes to the conclusion that the whole filament of 

 the primary and secondary, and probably also that of the tertiary, 

 mesenteries is ectodermic in origin, and that the whole of the 

 digestion of the animal is performed by these filaments, and draws 

 the important deduction that the stomodseum of Actinozoa is not 

 comparable with that of the Triploblastica, but is rather, with 

 the mesenterial filaments, the homologue of the whole gut. The 

 so-called endoderm is homologous with the mesoderm of Triplo- 

 blastica, and the Actinozoan polyp ought to be regarded as a Triplo- 

 blastic form. 



The second of the morphological papers is by Mr. J. J. Lister on 

 Astrosclera Willeyana, the type of a new family of spouges. This is 

 a very remarkable organism, with a massive calcareous skeleton of 

 polyhedral elements united to form a rigid skeleton and excluding 

 the soft parts, an arrangement which is only approached among 

 living sponges in the genus Pelrostoma. Among several points in 

 which Astrosclera differs from the rest of the Porifera may be men- 

 tioned the absence of a central atrial space, the minute size of the 

 flagellated chambers, and the peculiar form of the flagellated cells, 

 * As shown hv Mr. G. S. Miller, Jun. 



