NORTH AMERICAN LATER TERTIARY AND QUATERNARY BRYOZOA. 149 
so that the bottom of the peristome can be seen. The zooecia are sometimes 
bordered by a salient thread (fig. 13). The ovicell is very small (fig. 11). In the 
the interior the olocyst is perforated by very small pores corresponding to the 
large widened pores of the superposed tremocyst. 
Occurrence. —Pleistocene: Santa Monica (rare) and Santa Barbara, California 
(common). 
Habitat.— Pacific: Coronado Islands (24-29 meters). 
Plesiotypes. —Cat. No. 68652, U.S.N.M. 
Genus PALMICELLARIA Alder, 1864. 
1864. Palmicellaria Alder, Description New British Polyzoa, Quarterly Journal Microscopical 
Society, new ser., vol. 4, p. 100. 
The apertura is orbicular, semicircular, or semielliptical. Neither lyrula nor 
cardelles are present. The ovicell opens in the peristomie. The frontal is a granular 
pleurocyst, surrounded with areolar pores. The peristomie is much developed. 
Often an avicularian mucro partially hides the apertura. 
Genotype.—Palmicellaria elegans Alder, 1864. 
Range.— Miocene to Recent. 
The known species of this genus are: 
Palmicellaria elegans Alder, 1864. 
Palmicellaria ( Millepora) skenei Solander, 1786. 
Palmicellaria ( Eschara ) lorea Alder, 1864. 
Palmicellaria inermis Jullien, 1882. 
Palmicellaria tenuis Calvet, 1907. 
Structure.— The species of this genus are garnished with areolar pores and they 
therefore do not belong to the genus Porella Gray, 1848, as we have limited it. The 
absence of the lyrula and of cardelles distinguishes it from Smittina. 
Historical. —For a long time, on the authority of Waters, the species of this 
genus have been classed in the genus Porella Gray, 1848, because the known man¬ 
dibles are identical. The opercula and mandibles of Palmicellaria skenei Solander, 
1786, are indeed those of Porella. The mandible of P. lorea Alder, 1864, is also that 
of Porella, but the operculum is semielliptical and of quite a divergent type from 
other Porellas. The chitinous appendages of the genotype and of the other species 
are unfortunately unknown. 
All of the species cited having without exception the same characteristic of 
calcification, namely, a granular pleurocyst surrounded by areolar pores, we believe 
that it is necessary to maintain Alder’s genus, although it does not appear to us very 
well marked. 
PALMICELLARIA cf. INERMIS Jullien, 1882. 
Plate 4, fig. 13. 
Our figured specimen is too incomplete to be named with certainty, but we are 
introducing it to call attention to the genus in the early Miocene. This specimen is 
deprived of ovicell and its aperture is invisible. It approaches Palmicellaria inermis 
Jullien, 1882, but it differs from it in its larger micrometric measurements and in its 
apertura, which does not appear transverse. 
Occurrence. —Miocene (Bowden horizon): Santo Domingo. 
Plesiotype. —Cat. No. 68653, U.S.N.M. 
