NORTH AMERICAN EARLY TERTIARY BRYOZOA. 
221 
FLORIDINA BIFOLIATA, new species. 
Plate 35, fig. 5. 
Description. — The zoarium is bilamellar with curved fronds. The zooecia are 
distinct, quite elongated, separated by a deep furrow; the mural rim is smooth, 
wide, little salient; the cryptocyst is of little depth, of the same length as the 
opesium. The opesium is large, trifoliate, elongate; the opercular portion is small 
and separated from the opesiular region by two, little prominent teeth; the poly- 
pidian convexity is little salient, non symmetrical. Tire onychocellariunr is larger 
than the zooecia, quite elongated, fusiform, with spatulate beak ; the opesium is 
oval, the point above. 
Measurements. — Opesium r7m=0.25 mm. 
of zooecia]/<9=0. 20-0.22 mm. 
Zooecium 
f/",3= 0.50-0.52 mm. 
1/3=0.35-0.4:0 mm. 
Opesium f hon=0A0 mm. 
of onychocellarial /<m=0.11 mm. 
Onychocellariunr 
Lon— 0.80 mm. 
7on=0.30 mnr. 
Affinities.- — This species has a bilamellar zoarium like Floridina granulosa; 
it differs from it in the absolutely smooth frontal, and its onychocellariunr much 
longer than the zooecia. 
Occurrence . — Lower Jacksonian (Moodys marl) : Jackson, Mississippi (rare). 
Holotype.— Cat. No. 63981, U.S.N.M. 
FLORIDINA ONYDENTATA, new species. 
Plate 35, fig. 9. 
D escription. — The zoarium is unilamellar, creeping over algae. The zooecia 
are distinct, wide, ogival; the cryptocyst is shallow, concave, oblique to the 
opesium, finely granulated ; the opesium is transverse or trifoliate. The opesiules 
are nearly complete and linear. The polvpidian convexity is very long and often 
united with the opesial processes. The onychocellariunr is larger than the zooecium ; 
its opesium is triangular and toothed , with a large spine on its proximal border. 
Measurements. — Opesium f/m=0. 14—0.20 mm. 
(including opesiules) |./u= 0.20-0.24 mnr. 
Onychocellariunr 
Lon= 0.90 mm. 
lon=0.50 mnr. 
Zooecium 
j Z/3= 0.50— 0.60 mnr. 
1/3=0.30-0.40 mnr. 
Variations. — It is probable, that the pivot of the mandible was situated a little 
above the opesial tooth; this indicates that there were on each side two bundles 
of mandibular elevator muscles. 
The size of the opesiules is evidence of vigorous parietal muscles, necessary, 
moreover, for the zoarial hydrostatic system of this robust species. 
We have observed a true zooecium having the form of an onychocellariunr. 
More than once it has been proved that this organ is only a modified zooecium, 
and that every variation of one occasions a corresponding variation in the other. 
