176 THE DEVONIAN OF MISSOURI. 



DESCRIPTION OF SPECIES. 



Porifera 

 Class SPONGIAE 

 Order Lithistida, Suborder Eutaxicladina 

 Genus Hindia Duncan 



Hindia fibrosa (Roemer) 1 

 Plate 40, figures 1-4 



Clamopora fibrosa F. Roemer (not Goldfuss), 1860, Sil. Fauna des Westl. Tenn., p. 20, 



pi. II, fig. 2. 

 Astylospongia inornata Hall, 1863, 16th Ann. Rept. N. Y. State Cab. Nat. Hist., p. 70. 

 Hindia sphaeroidalis Duncan, 1879, Ann. & Mag. Nat. Hist., ser. V, vol. IV, p. 84, 



pi. IX. 

 Hindia fibrosa Hinde, 1883, Cat. Foss. Sponges Brit. Mus., p. 57, pi. XIII, fig. 1. 

 Hindia sphaeroidalis Rauff, 1894, Palaeospongiologie, pt. 1, p. 335, pis. 15-17, figs. 



1-4. 2 

 Hindia sphaeroidalis Girty, 1899, U. S. Geol. Surv., 19th Ann. Rept., pt. Ill, p. 552. 

 Hindia fibrosa Weller, 1903, Pal. N. J., vol. Ill, p. 297, pi. XXXII, figs. 1, 2. 

 Hindia fibrosa Clarke, 1908, N. Y. State Mus., mem. 9, pt. 1, p. 116. 

 Hindia fibrosa Clarke, 1909, N. Y. State Mus., mem. 9, pt. 2, p. 50. 

 Hindia sphaeroidalis Swartz, 1913, Md. Geol. Surv., L. Dev., p. 195, pi. XVII, figs. 1-4. 



Description — "Spherical, consisting of minute spicules uniting to form a series of 

 delicate, straight canals which radiate from the center of the sponge and increase by 

 bifurcation. The canals open upon the surface by polygonal orifices. The minute struc- 

 ture of this species was worked out by Rauff, and subsequently discussed critically by 

 Hinde, Ulrich and Girty. 



"Rauff showed that it consists of spicules, each of which bears 4 rays which diverge 

 from a common center. Three of the rays are stout, slightly curved, concave on the 

 inner side denticulate on the outer side and have expanded denticulate extremities. 

 The fourth ray is small and directed towards the exterior. It is often abortive. The 

 whole structure consists of superimposed series of these spicules. The manner in which 

 they unite to form the cancals is illustrated diagrammatically in fig. 3 [p. 196]. Three 

 spicules, whose centers form the angles of the cell, lie on one level while three alter- 

 nating spicules, whose centers are dotted in the diagram, lie at a slightly higher level 

 in the structure, their rays descending obliquely upon the rays of the first set, the third 

 layer repeating the first, etc. In this manner walls are built up around the canals which 

 are perforated by openings, placing the interior of the adjacent canals in communication. 

 The form of an individual spicule and the manner in which it articulates with its neigh- 

 bors is shown in fig. 4 [p. 196] while the manner in which they unite to form the walls 

 of the canal is shown in fig. 5 [p. 197]. Excellently preserved specimens showing the 

 inner structure are found at Keyser, West Virginia. 



"Position of the genus has been much discussed. Steinmann regarded it as a form 

 of Favosites. Rauff determined its true character, showing that it is a sponge and 

 regarded it as one of the siliceous sponges. 



"Diameter of spheres, 25 mm. or at times a little greater. They are frequently 

 somewhat distorted by compression." — Swartz, 1913. 



Dimensions — Mean diameter of sponges 7.8 to about 48 mm. 



'See Clarke, J. M., N. Y. State Mus., Mem. 9, pt. 2, pp 50-51, 1909. 



•For additional references through 1895, see Md. Geol. Surv., L. Dev., p. 195. 



