248 Description ofneio Lower Silurian Sponges. — Ulrich. 
The canals are larger, more irregular, and less numerous 
than in C. endoceroidea. 
CYLINDBOCCEIilA MINNESOTENSIS, n. sp, 
This species differs from the preceding ones in being almost 
perfectly cylindrical (^. e. allowing for a slight amount of com- 
pression apparent in all the specimens) the average taper in a 
length of 40 mm. being rarely more than 1 mm. Most of the 
fragments vary in diameter between 10 and 15 mm., but it is 
sometimes a mm. more or less. Basal extremity not satis- 
factorily shown in any of the specimens ; apparently truncate. 
The cloaca must have been narrow since it, like the internal 
portion of the canal system, has in every case been entirely 
obliterated by the crystallization of the calcite of which the 
specimens are composed. The surface is smooth and may, ac- 
cording as the dermal layer remained or had been removed at 
the time of fossilization, exhibit very few or comparatively 
abundant canal apertures — more irregularly distributed, how- 
ever, and not nearly so numerous as in the other species. The 
canals are rounded and vary in diameter from less than 1 to 
2.5 mm. 
Formation and locality : Trenton shales. Specimens of 
this species, though not common, have been noticed at Minne- 
apolis, St. Paul and Fountain in Minnesota. 
OYIilNDROCCELIA MINOR, n. sp. 
Of this species I have two small specimens. They were 
found in the upper siliceous beds of the Trenton group at a 
long cut for the Cin. South. R. R., just south of the Harrods- 
burg Junction. On one of them the lower end is truncate, 
about 7 mm. in diameter, and shows at the centre a round 
opening. The specimen is 18 mm. long and 12.5 mm. in diam- 
eter at its upper end. The other is 22 mm. long, between 10 
and 11 mm. in diameter above and tapered downward appar- 
ently to a point the lower extremity being imperfect. The 
surface of both examples is smooth and exhibits a moderate 
number of irregularly distributed, small, subequal, canal 
mouths, averaging 0.6 to 0.7 mm. in diameter. In both speci- 
mens the canals seem to have extended from the outer surface 
to the center of the sponge. If a cloaca was present in the 
species it must have been either very narrow or unusually 
shallow. 
