VENTEICULITES. 113 



spaces between the vertical ridges so conspicuously as in the Chalk examples. It is 

 probable that T. Smith's figure of V. striatus has been drawn from one of the flint- 

 inclosed examples of this species. 



This species is readily distinguished by the great thickness of the wall and the 

 characters of the outer surface. Though no description accompanies "Woodward's 

 figure, the examples from Norwich in the Museum collection enable me to identify 

 the forms which he has placed under this name. Unfortunately the descriptions of 

 species given by Toulmin Smith are very meagre and incomplete, and many of his 

 figures are diagrammatic, so that reliance cannot be placed on them*. I have care- 

 fully examined Smith's specimens in the Museum, and regard the forms referred by 

 him to V. bicomplicatus, V. lati}}licatus, V. striatus, and V. radiatus as belonging to 

 the present species. 



Distrihution. Upper Chalk: Norwich; Clopton, Suffolk ; Heytesbury, Beckhamp- 

 ton, Moncton-Bassett, Norton-Bavant, Wiltshire ; Wolsk, Volga, Russia {coll. Bay- 

 field, Cunnington, T. Smith). 



Venteiculites ceibrosus, Phillips, sp. (Plate XXVI. figs. 2, 2 a.) 



1829. Spongia cribrosa, Phill. Geol. Yorkshire, t. 1. f. 7. 



1864. Ventriculites multicostatus, F. A. Roemer, Palseont. Bd. 13, p. 19, t. 8. f. 1. 



Sponges elongated, narrow, funnel-shaped, very gradually tapering from the summit 

 to the base ; the root-processes usually spring from the basal end of the funnel, but 

 in some instances a short stem intervenes. The wall is 6 mm. in thickness where it 

 has not been compressed. A fairly complete specimen is 240 mm. in length by 

 55 mm. in width at the summit. 



The outer surface is reticulate; the ridges of the wall, about 12 mm. in width, 

 inosculate, so as to form elliptical interspaces, about 2-7 mm. in length by 1 mm. in 

 width, which, in some, though not in all the specimens, are disposed in quincunx. 

 The inner surface of the wall is concealed by the matrix. No spicular structure has 

 been preserved. 



This species, so far as can be judged from the unfavourable condition of the 

 specimens, differs from V. infundihuliformis principally in its thinner wall and the 

 smaller size of the ovate apertures of the outer surface. Phillips's figure is very 

 inexact, but there can hardly be a doubt respecting the form which he intended to 

 represent, since no other at all resembling it is found in the Chalk at Flamborough. 

 The sponge which F. A. Roemer has referred to this species (Nordd. Kreide, p. 9, 



* It may also be mentioned here that the type of Toulmin Smith's Ventriculites tessellatus (Ann. & Mag. 

 Nat. Hist. 2nd ser. vol. i. p. 211, t. 13. f. 2, 3, 4), now in the Museum, consists only of the impression of 

 the outer surface of a small fragment of a sponge on a small piece of chalk. No spicular structure can be 

 discerned, and it is doubtful whether the form even belongs to Ventriculites. The characters shown are 

 altogether insufficient for specific determination. 



Q 



