STELLISPONGIA.— SESTEOSTOMELLA . 187 



In a transparent section of a specimen from the Coral Rag at Suffield, in York- 

 shire, the fibres appear as narrow, open, anastomosing bands, from -14 to -3 mm. in 

 width ; they are composed of relatively large three- or four-rayed spicules with an 

 exterior layer of smaller sinuous apparently irregular three-rayed forms. 



Distribution. Coral Rag: Lyneham, Wiltshire ; Suffield, Yorkshire. Upper Jura: 

 Randen. 



Stellispongia glomerata, Qiiensf. sp. 



1858. Spongites glotneratus, Quenst. Der Jura, p. 695, t. 84. f. 10, 11. 



1840-47. Cnemidium stdlatum, Mich, (non Goldf.) Icon. Zooph. p. 115, t. 26. f. 8. 



1859. Didemospongia Thurmanni, Etallon, Letli. Brunt, p. 422, t. 59. f. 3. 



1859. SteUisponyia pertusa, aperta, hybrida, ei glomerata, EtaUon, ibid. pp. 423, 424, t. 59. 



f. 4-7. 

 1878. ateUispongia glomerata, Zitt. Studien, III Ab. p. 40. 



In a transverse microscopic section of a specimen from Basle the fibres very openly 

 anastomose ; they are about '28 mm. in width. The minute structure resembles that 

 oi S. coralUna. 



Distribution. Upper Jura : Giengen, Wiirtemberg ; Basle. 



Stellispongia semicincta, Quenst. sp. 



1878. Spongites semicinctus, Quenst. Petref. Bd. 5, p. 214, t. 125. f. 2-9. 

 1878. Stellispongia semicincta, Zitt. Studien, III Ab. p. 40. 



In the Woodwardian Museum at Cambridge there is an imperfect specimen from 

 the Coral Rag at Scarborough, which, so far as I am able to determine, appears to 

 belong to this species. It had been referred to Spongia floriceps, Phill. ; but the 

 figure of this species in the ' Geology of Yorkshire,' pi. 3. f 8, is insufficient for 

 comparison. 



Distribution. Upper Jura: Randen; Giengen. Coral Rag: Scarborough, York- 

 shire. 



Genus SESTROSTOMELLA, Zittel, 1878. 



SESTEOSTOMELLA CKIBEATA, Quenst. sp. 



1878. Spongites [Nudispongia) cribratus, Quenst. Petref. Bd. 5, p. 220, t. 125. f. 14-18. 

 1878. Sestrostomella cribrata, Zitt. Studien, III Ab. p. 41. 



The fibres, as seen in a transparent section, are about "12 mm. in width ; their 

 spicular structure is nearly entirely obliterated. 

 Distribution. Upper Jura: Randen, Switzerland. 



2b2 



