388 Mr. H. J. Carter on the " Tuhulations Sableuses " 



Grayi^ are gathered into short, broken, circular lines. (This 

 form is equally common to the Ventriculites and Cwlojptycliium^ 

 but with long spines). 



LiTHiSTiNA. Among the remains of the siliceous skeletons 

 of the Lithistina, which are bj far the 'most abundant and 

 most perfect in species and different forms of spicules respec- 

 tively (Rutot, figs. 9-11, 22-26, 43, 45, and 46), is one (fig. 9) 

 which is very like the surface or dermal large spicule of 

 Corallistes {Dactylocalyx) BowerhanMi -^ while the more com- 

 plicated stellate forms (figs. 43, 45, and 46), each of which 

 has a short pointed vertical shaft, indicative of its surface- 

 origin (generally broken off), are equally numerous, varied, 

 and beautiful in their forms. 



Geodina. Small siliceous balls (Rutot, figs. 36 and 37), 

 " zone-spicules " (figs. 12, 13, and 20, 21), " forked " and 

 "anchor-heads" respectively (figs. 16-18), and "body-spi- 

 cules " (figs. 1-4), indicate the presence of Oeodia^ as well as 

 that of Stellettina^ of which, respectively, there are, in all 

 probability, the remains of several species. That form of 

 " zone-spicule " (figs. 20 and 21) which has a curved shaft in 

 addition to produced fui'cate arms expanded florally and fre- 

 quently very unequal in length, abounds also in the Upper 

 Greensand of Haldon Hill, near Exeter, to which, together with 

 the other spicular elements of Geodia, I have given the name 

 of Geodiahaldonensis ('Annals,' 1871, vol. vii. pi. x. figs. 67 

 and 68) . It is equally common also in the cavities of English 

 chalk-flints ; but I have never seen any sponge of the present 

 day bearing the zone- or large furcate spicules like it ; so this 

 species may have ceased to exist. 



DONATINA. The globo-stellates of two kinds of Donaiia 

 appear to be present, as indicated by their forms respectively — 

 of which fig. 35 is one ; and the other is like the globo-stellate 

 of the present day in D. lyncurium, which is also common in 

 the cavities of the chalk-flints in England. 



Ophioehaphidites is also common here (Rutot, figs. 5 

 and 29), as well as in the Upper Greensand of Haldon Hill, 

 and existing at the present day ('Annals,' 1876, vol. xviii. 

 p. 458.) 



DiATOMACE^. The disks of a cycloid diatom are very 

 abundant (figs. 38, 39, and 39 a, J), presenting two forms, viz. 

 one simple like a flat drum, and the other the same, but with 

 depressions on it, in the form of a " Maltese cross," extending 

 from the centre to the circumference on both sides, in such a 

 way that the prominent or raised parts on one side correspond 

 to the depressions on the other, thus giving the edge, when 

 viewed laterally, an undulated appearance like Gyclotella 



