40 BRITISH FOSSIL SPONGES. 



respecting the skeleton of Astylospongia, and now regards it as consisting of 

 simple rodlike spicules branching at both ends. By the interlocking of the 

 branching extremities the nodes are formed. The family Astylospongida is 

 removed from the Heractinellidse and placed with the Anomocladine family of 

 lithistids. The previous definition of the characters of this family is altered, 

 and the elementary spicules of the skeleton are stated to consist of simple, 

 straight or curved, rod-like spicules with branching extremities. In the family 

 are included Astylospongia, Palaomanon, Protachilleum, Eospongia, Melonella, 

 Cylindrophyma, Mastosia, and the existing genus Vetulina. The genus 

 Didymosphara, Link, is regarded as equivalent to Cylindrophyma, Zitt. 

 Lecanella, Zitt., and Hindia, Dune, are placed in the family Megamorina. 



216. 1884 Pouta, P. Ueber isolirte Kieselspongiennadeln, aus der bohm. Kreide- 



formation. Ueber Spongiennadeln des Briisauer Hornsteines 

 [Sitzungsber. der. k. bohm. Gesell. der Wiss., pp. 1 — 14, 243 — 254, 

 3 pis). 

 Numerous detached spicules of tetractinellid, lithistid, and also of 



hexactinellid Sponges are described and figured. Many are similar to those 



occurring in the Cretaceous strata of England. 



217. 1SS4 Hixde, G. J. On the Structure and Affinities of the Family of the 



Receptaculitidas, including therein the genera Ischadites, Murch. 



( = Tetragonis, Eichw.) ; Sphasrospongia, Pengelly ; Acanthochonia, 



gen. nov., and Receptaculites, Defrance (Quart. Joum. Geol. Soc, vol. 



xl, pp. 795—849, Pis. XXXVI— XXXVII). 

 These fossils are regarded as siliceous hexactinellid Sponges in which one 

 ray of the regular spicule is modified to form a rhomboidal or hexagonal 

 plate. The history and geological distribution of the genera are given, as well 

 as a revision of the different species. 



218. 1884 Hinde, G. J. On Fossil Calcisponges from the Well-boring at Richmond 



(Quart. Joum. Geol. Soc, vol. xl, pp. 778—783, PI. XXXV). 

 Describes several new species of minute Sponges, in some of which the 

 spicular structure can be distinguished in thin sections. The strata from whence 

 they come are probably of Jurassic age. 



219. 1884 Hall, James. Descriptions of the Species of Fossil Reticulate Sponges, 



constituting the Family Dictyospongidas (Thirty-fifth Annual Report 



of the New York State Museum, pp. 465—481, Pis. 18—21). 



These bodies are described as fronds consisting of a reticulation of tubular 



spicules forming rectangular meshes, which alternate in size and strength, 



owing to the alternation in the size of the bundles of spicules. Three layers 



are stated to be present. No thing is stated of the form of the spicules, The 



