ELASMOCCELIA,— CONOCCELIA. 177 



Elasmoc(elia Fakringdonensis, Mant. sp. (Plate XXXIV. figs. 7, 7 a.) 

 1854. Tragos Farringdonensis, Mantell, Medals of Creation, vol. i. p. 229, f . 5. 

 1874. Tragos Farringdonensis, Davey, Transactions Newbury Field-Club, p. 14. 



Sponges with vertically compressed, upright, or fan-shaped walls, from 30 to 

 45 mm. in height and the same in breadth. The flattened summit is from 10 to 

 ]7 mm. in width, and exhibits numerous circular canal-apertures, about 1*25 mm. in 

 width, irregularly disposed from one to three diameters apart from each other. The 

 lateral surfaces are smooth, and show irregular pores between the fibres. The canals 

 appear to extend throughout the sponge in a generally vertical direction. 



The fibres of the interior form an open anastomosing mesh ; they are from '12 to 

 •2 mm. in thickness. The minute structure is not very distinctly shown in the 

 section examined ; it appears to consist of three- and four-rayed spicules with 

 straight arms : slender filiform spicules of the Corynella type are also present. 



The general form of this and the following species corresponds with that of 

 sponges of the genus Oculospongia, but the absence of a compact dermal layer 

 and the different characters of the spicular mesh separate them from this genus, 

 whilst in the large size and vertical extension of the cloacal tubes they resemble 

 typical forms of Elasmoccelia. 



Distribution. Lower Green Sand : Farringdon {coll. John Brown). 



Elasmoccelia Mantelli, Hinde, n. sp. (Plate XXXIV. fig. 8.) 



Sponges growing in short, upright, or lobed masses from an expanded base. An 

 average specimen is 22 mm. in height and 31 in breadth. The upper surface is 

 flattened or slightly convex ; it is penetrated by the apertures of numerous canals, 

 about 2-25 mm. each in width and about their own diameters apart. The fibres are 

 from "15 to "3 mm. in thickness. This species may be distinguished from the pre- 

 ceding by its form and the much larger dimensions of the canals. It appears to 

 be rare. 



Distribution. Lower Green Sand : Farringdon. 



Genus CONOCCELIA, Zittel, 1878. 

 Conoccelia ceassa. From. sp. 



1861. Siphonocoelia crassa, From. Cat. raisonne, p. 7, t. 1. f. 1, 1 a. 

 1878. Conoccelia crassa, Zitt. Studien, III Ab. p. 34. 



In a vertical transparent section of a specimen from Censeau the fibres exhibit a 

 somewhat similar structure to that of Sestrostomella ; they are mainly composed of 

 filamentous wavy spicules, so closely arranged in the direction of the fibre that it is 

 impracticable to determine if they are uniaxial or three-rayed forms; in the central 



2a 



