ORDOVICIAN FAUNAS. 135 
DESCRIPTION OF SPECIES IN THE TRENTON FAUNA. 
COELENTERATA. 
SPONGIAE. 
HINDIA PARVA Ulrich. 
Plater Vile Hiss. ie 
1889. Hindia parva Ulrich, Am. Geol., vol. III., p. 244. 
ISI parva W., & S., Pal. Minn. pt: 1) p. 79; pl. G, 
figs. 7-9. 
Description—“Sponges free, globular in form, with an even, 
rounded surface. Specimens vary between 5 and 10 mm. in diameter, 
but in a large proportion of the specimens seen the diameter varies 
but little from 7 or 8 mm.”—UlIrich. 
Remarks.—Specimens of a small, globular sponge have been recog- 
nized from various localities in the collections of Trenton limestone 
fossils. ‘They agree perfectly in external characters with the original 
description of Hindia parva, and are also indistinguishable from 
authentic specimens of that species from Wisconsin. Their condition 
of preservation is not such as to show the internal structure in thin 
sections. 
RECEPTACULITES OCCIDENTALIS Salter. 
Plate VI., Figs. 2-4. 
1859. Receptaculites occidentalis Salter, Can. Org. Rem., Dec. 1, 
pa 4o.; pl. LO, figs: 17: 
1884. Receptaculites occidentalis Hinde, Quart. Jour. Geol. Soc., 
Lond., vol. XI, p. 842, pl. 37, fies. 3-3 m. 
Description.—Sponge forming discoid or flattened, saucer-like ex- 
pansions, attaining a diameter of 200 mm., and having a thickness 
varying from 4 mm. at the centre of the disk to 12 mm. at the margin. 
