164 CALCAEEOUS SPONGES. 



1864. Verrucospongia submarginata, Laube, Denks. d. k. Akad. d. Wiss. Bd. 24, p. 237, 



t. 1. f. 11, 11a. 

 1878. Celyphia submarginata, Zitt. Studien, III Ab. p. 29. 

 1878. Testaspongia craniolaris, Quenst. Petref. Bd. 5, p. 539, t. 140. f. 29, 30. 

 1882. Celyphia submarginata, Steinm. Neues Jahrb. Bd. 2, p. 158, t. 6. f. 6-10, and 



t. 9. f. 3. 



Distribution. Trias : St. Cassian, Tyrol [coU. Klipstein). 



Genus HIMATELLA, Zittel, 1878. 



HiMATELLA MILLEPORATA, Milnst. sp. 



1841. Tragos milleporatum, Miinst. Beitr. iv. p. 29, t. 1. f. 17. 



1864. Lymnoretlules milleporata, Laube, Denks. d. k. Akad. d. Wiss. Bd. 24, p. 234, t. 1. 



f. 7 a, b. 

 1878. Himatella milleporata, Zitt. Studien, III Ab. p. 29. 



1878. Tragos milleporatum, Quenst. Petref. Bd. 5, p. 538, t. 140. f. 25, 26. 



1879. Himatella milleporata, Zitt. Neues Jalirb. p. 24. 



Distrihution. Trias: St. Cassian, Tyrol. 



Genus PERONELLA, Zittel, 1878. 



The definition of this genus by Prof. Zittel is based mainly on the form of the 

 sponge and the absence of any definite canal-system. The minute spicular structure 

 of the fibres is by no means uniform in the various species included in the genus ; 

 and Zittel suggested the probable necessity of splitting it up, when a better acquaint- 

 ance with the spicular structure of the different species would allow of a more natural 

 grouping based on the spicular characters. 



Though with respect to the Triassic species no fresh grouping is practicable on 

 account of the complete obliteration of the minute structure of the fibres, yet in 

 the species from Jurassic and Cretaceous strata the fibrous structure is, as a rule, 

 sufficiently well preserved to permit its characters to be defined. It consists of 

 relatively large and medium-sized three- or four-rayed spicules, the rays of which are 

 disposed in the central portion of the fibre, and are surrounded by similar, but 

 smaller, spicules ; in some instances the fibre is narrow, and almost exclusively 

 composed of the rays of the larger spicules. The borders of the fibre do not show 

 the sinuous spicules which characterize the genus Sestrostomella. I have not found 

 any simple acerate spicules in the fibres. 



The above definition will include all the Jurassic species which I have examined, 

 but it will exclude for example Peronella multidigitata, Mich, sp., which resembles 

 typical forms of Peronella in the absence of definite canals, but its spicular structure 

 is distinctly similar to that of the genus Corynella. As, however, the presence or 



