114 SILICEOUS SPONGES, 



t. 4. f. 2) differs from the Flaraborough examples by its apparently thinner wall and 

 the circular form of the surface-apertures; but, on the other hand, the V. muUi- 

 costatus of the same author, so far as can be judged from the descriptions and 

 figures, appears to be identical with Phillips's species. 

 Distribution. Upper Chalk : Flamborough, Yorkshire. 



Ventriculites angustatus, Rmmer, sp. (Plate XXVI. figs. 3, 3 «, 3 h.) 



1840. Scyphia angustata, Roemer, Nordd. Kreide, p. 8, t. 3. f. 5. 

 1854. Scyphia angustata, Morris, Cat. Brit. Foss. p. 29. 



Sponges narrow, funnel-shaped, occasionally compressed, gradually tapering from 

 the summit to the basal end. No stem or root has been preserved. The thickness 

 of the wall in a silicified specimen is 5 mm., in specimens preserved in chalk it is 

 about 3-5 mm. The length of what appears to be an average specimen is 95 mm., 

 and the summit width is 26 mm. 



The outer surface has an irregular reticulate aspect ; in places the ridges of the 

 wall, about -9 mm. in width, are disposed vertically, and connected by lateral exten- 

 sions, so as to leave transversely elliptical or irregularly subangular interspaces from 

 •8 mm. to 1'2 in width ; in other parts of the same specimen the disposition of the 

 ridges and interspaces is altogether irregular. The interior surface of the wall has 

 circular apertures, 1 mm. wide, and nearly the same distance apart, arranged regu- 

 larly in quincunx. 



The spicular structure of the specimens is nearly obliterated, but I have ascer- 

 tained the octahedral character of the nodes. The mesh appears to be irregular ; 

 the distance from node to node is -35 mm. The dermal layer, both of the outer and 

 inner surface of the wall, shows minute circular pores of different sizes. 



This species can be readily distinguished from the funnel-shaped forms previously 

 described by the characters of the outer surface. This closely agrees with Eoemer's 

 figure of the type in the Nordd. Kreide ; but it does not correspond with the forms 

 which the same author referred to the species at a later date under the name of 

 Cylindrospongia angustata*, nor with those which Ferd. Rcemerf and Quenstedt:^ 

 have referred to the species. This species appears to be rare. 

 Distribution. Upper Chalk : South of England. 



Ventriculites alcyonoides, Mantell. 



1808. An Alcyonite, Parkinson, Organic Remains, vol. ii. p. 213^ t. 10. f. 12. 



1816. Flint Alcyonite, W. Smith, Strata Identified, t. 3. f. 1. 



1822. Ventriculites alcyonoides, Mantell, Foss. South Downs, p. 176. 



• PalEBontograpliioa, Ed. 13, p. 22, t. 8. f. 10. 

 t GeoL Obersohlesien, p. 309, t. 30. f. 7, 8. 

 + Petrefaoten, Bd. 5, p. 457, t. 13G. f. 2-14. 



