On Astylospongidae awe? Anomocladina. 271 



XXXV. — On Astjlospongidas and Anomocladiua. 

 By Karl A. Zittel*. 



Dr. G. J. HiNDE, in his Catalogue of the Fossil Sponges in 

 the British Museum, which will form the foundation for all 

 future spongiological work in England, has expressed some 

 doubt as to the systematic position of the Astylospongidas. 

 The doubts long since communicated to me by Dr. Hinde by 

 letter, have induced me to make a new examination of the 

 skeleton of Astylospongia and Palceomanon^ for which I was 

 able to make use of a considerable number of thin sections of 

 most of the known species. 



Astylospongia and Palceomanoa in their external form, the 

 structure of their skeleton, and their canal-system stand in a 

 certain contrast with the Hexactinellidte. In no typical Hex- 

 actinellid genus does the skeleton form so thick and massive 

 a wall, in none is the root-tuft or a basal surface of adhesion 

 wanting, and that the canal-system of Astylospo7igia almost 

 exactly resembles that of certain Lithistidas, I have already 

 pointed out in my ^ Studien ' (Abtheilung i. p. 30 ; see 

 ' Annals,' ser. 4, vol. xx. p. 412). The skeleton consists of a 

 reticulated latticework, in which from six to nine rays issue 

 more or less regularly from thickened nodes and attach them- 

 selves by their extremities to neighbouring crossing knots of 

 the same nature. The skeletal meshes thus formed are some- 

 times triangular or quadrangular, sometimes irregularly poly- 

 hedral. 



If we compare this skeleton with that of other Sponges we 

 are struck, in the first place, with a resemblance to some 

 Dictyonina. The irregularity of the meshes, the deviation 

 from the rectangular position of the rays, is by no means un- 

 usual in typical Hexactinellidse j but in such cases, even 

 when tliere is great irregularity of the skeleton, the axial 

 canals always show the sex-radiate cross. Nothing of the 

 kind has ever been observed in Astylospongia. 



Prof. Martin t has very carefully described the skeleton of 

 Astylospongia almost simultaneously with myself, and arrived, 

 like myself, at the result that the Silurian genus was certainly 

 to be joined with the Hexactinellidte, but that nevertheless 

 considerable differences exist between Astylospongia and the 

 typical Hexactinellidse. Martin finds the most important 



* Translated by W. S. Dallas, F.L.S., from a separate copy, fui-nished 

 by the author, of his paper in the ' Neues Jahrbuch fiir Mineralogie,' 

 &c. 1884, Bd. ii. pp. 75-bO, Taf. i. & ii. 



t ' Archiv des Vereius der Freunde der Naturgeschichte in Mecklen- 

 burg,' Jahrg. xxxi. (_1877). 



