ZOOLOGY AND BOTANY, MIGKOSCOPY, ETC. 397 



cladia, wliicli is remarkable for its dendroid growth ; the branches 

 are hollow. Of the Staurodermidse of the collection the new forms 

 are Placotrema (allied to Porospongia), Cnididerma (distinguished by 

 having the level dermal surface divided up regularly into squares by 

 the arrangement of its spicules), and Plectoderma, differing slightly 

 from Didyophyton, but of which the form is unknown. The Callo- 

 dictyonidte have Porochonia, based on an old species of Ventriculites 

 provided with a delicate surface-tissue besides the usual dermal layer, 

 and ScleroJcalia, a nest-shaped sponge, with vertical rows of apertures 

 on the inner surface, and shallow canals leading from them. No new 

 Lyssacine Hexactinellid genera are described. 



The Calcarea, as defined by Dr. Hinde, are very numerous, owing to 

 the inclusion by him of the Pharetrones (distinguished by the possession 

 of a fibrous skeleton) in the group, in which course he follows Zittel 

 and the more recent views of Steinmann and Dunikowski ; this step is 

 in partial opposition to Carter and Sollas, who regard some, at any 

 rate, of its members as siliceous. Unlike Dunikowski, who places them 

 under the Leuconidae, he regards them as constituting a distinct 

 family ; he relies largely on the character of the fibre and the methods 

 of arrangement of the spicules in it, for his definition of genera. 

 Few species are described as new. The new genus Tremacystia unites 

 a number of already known species, distinguished by a metameric seg- 

 mentation of the sponge. Inoholia is distinguished by its form and the 

 absence of canals. TracJiysinia has a cylindrical form and may be com- 

 pound ; it is based on three new Jurassic species. Diaplectia has the 

 growth of Pharetrospongia, but contains tri- and quadriradiate spicules. 

 Baphidonema has elongate triradiate spicules like those of Gorynella. 

 Among the Calcarea, but as incertce sedis, is introduced Bactronella 

 n. g., from the Upper Jura ; it resembles the recent Leuconidse, but the 

 spicules are spinous. No Horny sponges find mention. 



Tables and lists are given showing the known distribution in time 

 of all the species, from which it appears that the Cretaceous beds 

 contribute to the collection by far the greatest number, viz. the large 

 total of 250 species, of which 103 are Lithistidae, 85 Hexactinellida, 

 and 46 Calcarea (including Pharetrones') ; the total number of species 

 enumerated is 399. A bibliography is given. 



Vosmaer's Manual of the Sponges.* — G. C. J. Vosmaer com- 

 pletes the review of the literature of sponges commenced in the first 

 instalment of this work.t He devotes seven pages to an account (A) 

 of the best methods of investigation, under the heads (1) Investiga- 

 tion of the soft parts. — Killing and preserving, staining, preparation 

 and preservation of sections, decalcification and desilicification. (2) 

 Investigation of the sTceleton. — Skeleton of the Calcareous Sponges, of 

 the true Horny Sponges, of the Siliceous Sponges. (B) Preservation for 

 collections. (C) Eearing larvae under the Microscope. For hardening, 

 absolute alcohol, picro-chloric and osmic acids, and corrosive sublimate ; 



* 'Dr. H. G. Bronn's Klasseu und Orduungen des Thierreichs. Band ix. 

 Porifera.' Lief. 3-5, 1884, pp. 65-144 (10 pls.V See this Journal, ii. (1882) p. 797. 

 t See this Journal, i. (1881) p. 611. 



