197 



ing the annulated rod so as to leave about one-third of its circumference 

 exposed to view. Sometimes the rod changes suddenly from one side 

 of the branch to the other. 



Occurrence. CHAMBERSBURG LIMESTONE (Tetradium cellulosum bed). 

 Fort Loudon, Franklin County, Pennsylvania. An abundant species in 

 the Decorah shales division of the Black Eiver in Goodhue County, 

 Minnesota, and at the same horizon in Mercer County, Kentucky. 



Collections. Maryland Geological Survey, U. S. National Museum. 



Order TETRACTINELLIDA 



Family HINDIIDAE 



Genus HINDIA Duncan 

 HINDIA PARVA Ulrich 



Plate L, Figs. 11-13 



Hindia parva Ulrich, 1889, Amer. Geol., vol. iii, p. 244. 



Hindia parva Winchell and Schuchert, 1895, Geol. Minnesota, vol. iii, pt. 1, 



p. 79, pi. G, figs. 7-9. 

 Hindia parva Weller, 1903, Geol. Surv. New Jersey, Pal., vol. iii, p. 135, pi. vi, 



fig. 1. 



Description. This small sponge forms free, rounded masses with a 

 smooth surface. Most of the specimens are about 7 mm. in diameter, 

 although this dimension varies between 5 and 10 mm. The internal 

 structure is very similar to the common Hindia sphaeroidalis Duncan 

 of the Silurian and Early Devonian, but the radiating canals of H. parva 

 are somewhat smaller, being not over 0.27 mm. in diameter. More 

 refined methods of study of these sponges will no doubt reveal other 

 important differences. 



Occurrence. MARTINSBURG SHALE (Sinuites bed). Chambersburg, 

 Pennsylvania, and Strasburg, Virginia. Black Eiver of Minnesota and 

 Wisconsin, Trenton of Kentucky, Tennessee, New Jersey and other states. 



Collections. Maryland Geological Survey, U. S. National Museum. 



