244 Description of new Lower Silurian Sponges. — Ulrich. 
those respects, the canals being scarcely more than one third 
as large. 
Formation and locality : The best specimens of D. mini- 
ma seen were found at a fine locality for bryozoa near Hano- 
ver, a small village in Butler county, Ohio. D. insolens, so far 
as known, is restricted to the middle beds of the group. 
STREPTOSPONQIA LABYRINTHICA, n. gen. et. sp. 
The specimen upon which this genus and species are found- 
ed is a fragment of a massive sponge. It is siliceous, over 
50 mm. long, 30 mm. high, and 25 mm. wide, and broken so as 
to show longitudinal and transverse sections. In the latter 
the sponge appears composed of labyrinthically intertwining 
vertical laminD3, nearly constantly 0.3 mm. thick, separated by 
tortuous and almost linear interspaces, with here and there an 
irregular angular open space not noticed to exceed 1 mm. 
in length. The vertical fracture shows that this remarkable 
intertwining is largely produced by connecting processes on 
the sides of the laminae. These are usually rounded in cross- 
section and occur at frequent but irregular intervals, while they 
are also of very unequal size, some being very small and others 
more than 1 mm. in diameter. Numerous small punctures 
also may be detected scattered among the connecting projec- 
tions. 
Spicular structure entirely destroyed. 
The systematic position of this genus is very uncertain, but 
the fossil is so remarkable that the propriety of naming it is 
believed to be beyond question. The sponge is not likely to 
be confounded with any other known to me and it is to be 
hoped that collectors will search for other specimens. The 
only one seen was found in the bed of a creek near Lebanon, 
Kentucky, in the banks of which the upper beds of the Cincin- 
nati group were exposed. 
HINDIA PARVA.n. sp. 
Sponges free, globular in form, with an even rounded sur- 
face. 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. 
The radiating canals are a little smaller than in the common 
H. spheroidalis Duncan, of the Niagara, being, as a rule, not 
over 0.27 mm. in diameter. H. incequalis Ulrich, from the 
lower or sponge beds of the Trenton limestone at Dixon, Illi- 
