122 Mr. H. J. Carter on Fossil Sponge-spicules of 



posit, "we shall find what we want ; but if we allow our expec- 

 tations to go beyond this, and seek for the minuter elements, 

 either in the shape of spines or tubercles on the large spicules, 

 or in that of the minute stellates or other spicules of this kind, 

 which most probably accompanied them in the sponges from 

 which they originally came, we shall be disappointed, at least 

 so far as our investigations have extended. And although it 

 w^ould be too hazardous to state that such minute elements are 

 entirely absent, still the effect of trituration at the time of de- 

 posit, and the subsequent solvent influence attending petrifac- 

 tion, together with our want of success in this way, preclude 

 all reasonable ho})e of their being present anywhere in such a 

 sandy deposit. Where whole masses or entire sponges, as 

 before stated, have become consolidated in the form of flint 

 &c., they may be preserved, as flies in amber ; but it seems 

 hopeless to hunt for them in this sandy grit. 



Nor is there much dependence, for the same reasons, to be 

 placed on the forms of the smaller spicules, such as figs. 51 

 and 52 ; for what may have carried away the minute spicules 

 and have affected the surfaces of the large ones, is not likely 

 to have spared those of the smaller ones, in which the altera- 

 tion in form would thus be proportionally more extensive and 

 disfiguring. 



Having now reviewed the illustrations in the accompanying- 

 plates generally, let us liastily go over the figures somewhat 

 more specially, which, while it entails a little repetition of 

 what has gone before, will serve to curtail much of the usual 

 tabular explanation. 



Of figs. 1 to 5 there can be no doubt that the latter be- 

 longed to a coral-sponge like Discodermia iJolydiscus, Bocage 

 (Journ.des Sc.Mathdmat.Phys. et Nat. Lisbonne, no. iv. 1869), 

 from which are copied our tw^o figures 8 and 9, being the 

 upper and lateral views respectively of the disk. It was pre- 

 viously called Dactylocalyx i)olydiscus by Dr. Bowerbank, for 

 whose illustrations, of a similar kind, see Proceed. Zool. 8oc. 

 Lond. 1869, pi. vi. figs. 10 &c. ; since then it has been figured 

 by Schmidt under the name of Coralli'sfes jyolydiscus (Atlant. 

 Spong. Faun. Taf. iii. fig. 8, 1870), of which our fig. 7 is a 

 tracing. Bocage found his specimens implanted on a piece 

 of Halichondria ; but from what locality is not mentioned. 

 That described by Schmidt was obtained at the minimum 

 depth of 152 fathoms in the Gulf of Florida. 



Neither Bowerbank nor Du Bocage gives his figures of the 

 disk that amount of indentation which is found in Schmidt's ; 

 but if the latter be not another species, then it is probable that 

 my figures 3, 4, and 5, which, with their like, abound in the 



