HINDIA. 115 



Genus. — Hindia, Duncan. 

 1879. Ann. and Mag. Nat. Hist., ser. 5, vol. iv, p. 84. 



Syn. — Calamopora, F. Boemer (non Goldfuss), Steinmann ; Spheerolites, Hinde. 



Sponges spherical or sub-spherical in form, free, without stem or any surface 

 of attachment. The body of the Sponge is traversed throughout by straight, 

 simple, subcylindrical or prismatic, sub-equal canals, radiating, in close proximity 

 to each other, from a central space, and opening freely at the surface. The 

 skeleton consists of spicules generally with four rays (though occasionally only 

 three are developed) which extend from a compressed central node. Three of the 

 rays are sub-equal, whilst the fourth is truncated. The rays terminate in flattened, 

 circular, irregularly digitate expansions, which firmly clasp the nodes and convex 

 surfaces of the rays of adjoining spicules in such a manner as to form an extremely 

 regular meshwork, with transversely elliptical interspaces. 



Specimens of this genus from West Tennessee were originally described as 

 corals by F. Roemer 1 under the name of Calamopora fibrosa. They occur as 

 silicified casts, in which the original structure has been entirely removed ; and in 

 this condition they resemble very closely small silicified corals. Without being 

 aware of F. Roemer's reference of the forms to corals, I made a similar mistake 

 respecting forms which I had collected from New Brunswick, erroneously regard- 

 ing them as perforate corals, which I named SpJwerolites.* My specimens were 

 afterwards submitted to Prof. M. Duncan, 3 who recognised the spicular nature of 

 this skeleton, and constituted them into a new genus of Sponges, which he named 

 Hindia. The original silica in these specimens had been replaced by calcite, but 

 Prof. Duncan, maintaining that the skeletons were originally of calcite, principally 

 on the ground of the supposed presence in them of a parasitic Alga, regards the 

 forms as Calcisponges, representing a former mimetic and calcareous group of 

 Spongida. Their general structure corresponds so closely with that of Lithistid 

 Sponges that I felt justified in placing the genus in the Anomocladina family of 

 this group ; 4 Zittel, 5 however, regarded the genus as more properly coming within 

 the Megamorina family. A later writer, 6 Dr. Steinmann, has asserted that the 

 genus exhibits none of the characters of Lithistid Sponges, and that it really 



1 'Die silur. Fauna d. westl. Tenn.,' p. 20. 



2 * Abstract Proceedings Geol. Soc.,' 1875, No. 305. 



3 ' Ann. and Mag. Nat. Hist.,' ser. 5, vol. iv, p. 84, 1879. 



4 ' Cat. Brit. Foss. Spong.,' p. 57, 1883. 



5 ' Neues Jahrb.,' 1884, Bd. ii, p. 79. 



6 Ibid., 1886, Bd. i, Heft i, p. 91. 



