116 BRITISH PALASOZOIC SPONGES. 
belongs to perforate corals like Favosites. In reply to this, Dr. H. Rauff! showed 
more clearly than had been done by previous writers the spicular characters and 
the structure of the genus, which, however, he placed in the Tetracladina family 
of Lithistids. Prof. Duncan,’ still relying on the supposed parasitic borings in 
the Sponge, has reasserted that it was an originally calcareous organism. What- 
ever may be the nature of the bodies which Prof. Duncan refers to Alga, it is 
evident, from the fact that they are present in the siliceous matrix of the Sponge, 
and apparently do not penetrate the spicules themselves, that they have no bearing 
on the original mineral constitution of the Sponge itself. The specimens, in which 
the skeleton is now of carbonate of lime, present the same evidence that this mineral 
is a replacement of silica, as the calcified examples of Astylospongia and other 
Lithistid Sponges from the Silurian strata, and there is but little doubt that as in 
these forms the original spicular structure of Hindia was siliceous. 
The character of the spicules, consisting of a central node with diverging rays, 
and their mode of union to form the skeleton by the clasping of their expanded 
extremities to the nodes of adjoining spicules, appear to me to indicate their position 
in the Anomocladina family. 
Hindia makes its first appearance in Ordovician strata in Ayrshire and in 
Illinois ; it is more abundant in Silurian strata in various places in North America, 
Russia, Isle of Gothland, Sweden, and in the Drift deposits of Northern Germany. 
Detached spicules, referable to the genus, are also present in the Carboniferous 
Limestone of Sligo, Ireland, and the Yoredale Beds of Yorkshire. 
5. Hinpra risrosa, Ff. Roemer sp. Plate LX, figs. 3, 3 a—3 e. 
1860. Catamopora FrBROsA, Ff. Roemer (non Goldfuss). Die silur. Fauna d. 
westl. Tenn., p. 20, 
pl. ii, figs. 2, 2a, 6. 
1861. Monricunreora PETROPOLITANA (in part), #. Roemer. Die fossile Fauna 
von Sadewitz, p. 28. 
18638. AsryLosponera tnornNavTA, Hall. Sixteenth Annual Report State Cabinet 
Nat. Hist., p. 69. 
1875. Spumropires Nicuoxnsoni, Hinde. Abstract Proc. Geol. Soc., No. 305. 
1879. Hinpia spHmROTDALIS, Duncan. Ann. and Mag. Nat. Hist., ser. 5, vol. iv, 
p. 84, pl. ix. 
1883. —  rrprosa, Hinde. Cat. Foss. Sponges, p. 57, pl. xiii, figs. 1, 1 a, 10. 
1884-5. — _ F. Roemer. Lethea erratica. Paleontolog. Abhandl., 
2te Bd., Heft 5, p. 310, pl. xxv, fig. 17, 
1 ¢Sitzungsber. der niederrhein. Gesellsch. zu Bonn,’ 1886. 
2 «Ann, and Mag. Nat. Hist.,’ vol. xxiii (1886), p. 226. 
