PLATE VII. 
Figs. 2, 4, and 8 are of the natural size, all the rest are magnified 18 diameters. 
Risse: 
la. 
1b. 
Fig. 2. 
2a. 
Ss: 
Ss: 
DISCOTRYPA ELEGANS, Ulrich. View of the surface ee one half 
of a monticule, ; 
Vertical section through the entire jensth of the paves 
Tangential section. The cells under the apex of a monticule being cut 
at a lower level than those upon its slopes, have thinner walls,. 
ASPIDOPORA AREOLATA, n. sp. A small specimen of the natural size, 
The surface enlarged to show the oval cell-apertures, many of which 
are covered with a centrally perforated operculum, the spiniform 
tubuli, and interstitial cells. 
. Tangential section of this species. 
. Longitudinal section showing the entire thickness of the zoarium. 
. PETIGOPORA GREGARIA, n. sp. A group of four individuals growing 
upon an example of Heterotrypa frondosa. Natural size, 
. The surface of this species enlarged. 
. Tangential section of same. 
. A longitudinal! section showing the entire length of the tubes. 
. PETIGOPORA ASPERULA, n. sp. A specimen of this species growing as 
usual upon Strophomena alternata. Natural size, 
. Surface enlarged to show the prominent and numerous spiniionmn taba 
. Tangential section enlarged. 
». Longitudinal section through the entire thickness of the zoarium. 
. SPATIOPORA ASPERA, n. sp. One of the groups of larger cells and 
spiniform tubuli marking the surface, 
. Tangential section of this species, representing the jreeulee outs in 
the interspaces between the groups of large ones. 
. A longitudinal section showing the entire thickness of the zoarium. 
3. SPATIOPORA MACULOSA, n. sp. The surface of this species enlarged. 
The figure shows the mee tubuli, and a portion of a group of 
larger cells, 
. SPATIOPORA LINEATA, 0D. sp. The ddtaee enlarged : 
. SPATIOPORA MONTIFERA, n. sp. A portion of a specimen of ie 
species showing the size and arrangement of the monticules. 
Natural size, 
PAGE 
163. 
164 
166 
167 
167 
168 
