112 Mr. H. J. Carter on Fossil Siyonge-spicules of in the ribs, from which they branch off laterally towards the furrows. Mr. Davidson's specimens were taken in from 45 to 50 fathoms water, on the Agulhas Bank, south coast of Africa. The locality has suggested to me the generic name which has been given to the species. • EXPLANATION OF PLATE XI. Fig. 1. Natural -sized outline of Aytdhasia Davidsunii. Fig. 2. Same species, dorsal view, showing position of the foramen. Fig. 3. Same species, ventral view. Fig. 4. Same species, lateral view. Fig. 5. Same species, interior of d(jrsal valve, showing loop, teeth, and cardinal muscular fulcrum. Fig. G. Same species, profile view of the loop. Fig. 7. Same species ; view of the interior of ventral valve and of the upper aspect of the beak, the latter showing the area (ii), del-tidium (h), foramen (c), indexed sides of the beak (d), and one of the sutures bounding the area (e). Fig. 8. Represents tubuli characteristic of Terehrafulina caput-serpentis. I am very much indebted to Mr. Davidson for finishing oil" my rough sketches of the above fif^ures. XIV. — On Fossil Sjioncie-spicuhs of the Greensand compared with those of existing Species. By H. J. Cartee, F.R.S. &c. [Plates VII.-X.] The material which furnished the fossil sponge-spicules from which all the tigurcs, except three, in the accompanying four plates were taken, was found by my kind and intelligent friend Mr. W. Vicary, of Exeter, in the " Up]:)er Greensand " of Haldon Hill, near Exeter, and of Black Down, near Cullompton, respectively, — the former portion in a stratum of greenish-brown, loose, fine sand, about 25 feet thick, and the latter in a rounded pebble of the same nature, more consolidated. They were brought to my notice by Mr. Vicary and my friend J\Ir. Parfitt, also of Exeter, who read a valuable paper on them at the meeting of the " Devonshire Association for the advancement of Science, Literature, and Art," in July last, which was subsequently printed in their ' Transactions ' for 1870. The frequently loose state of the whole material, in which the spicules are sometimes almost as numerous as the grains of sand among which they are imbedded, together with their large size, render their extraction with a simple but powerful lens and a hair-pencil a work of time rather than one of dif-ficulty.
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