NORTH AMERICAN LATER TERTIARY AND QUATERNARY BRYOZOA. 
105 
SCHIZOPODRELLA MUTABILIS Canu and Bassler, 1919. 
Plate 6, figs. 3-5. 
1919. Schizopodrella ? mutabilis Canu and Bassler, Geology and Paleontology of the West Indies, 
Bryozoa, Publications of the Carnegie Institution of Washington, no. 291, p. 90, pl.6 , 
figs. 3-5. 
Description .—The zoarium is unilamellar, tubular; it incrusts the fine radi- 
cells of algae. The zooecia are little distinct, elongate, elliptical; the frontal is 
little convex, surrounded by areolar pores and garnished with some large tremo- 
pores. The apertura is elongate, oval, with a wide rimule separated from the 
anter by two salient condyles. 
Measure ments .—Apertura 
Aa = 0.18-0.20 mm. 
Za = 0.12 mm. 
Zooecia 
Lz = 0.70 mm. 
lz = 0.34 mm. 
Affinities .—The very thick incrustation of the tremocyst renders the aspect of 
this species quite changeable and sometimes absolutely unrecognizable. We have 
not discovered the ovicell, so the classification naturally remains doubtful. It is 
possible that our specimens represent the incrusting base of some branching form 
like GemelliporeUa punctata Canu and Bassler, 1919, but until the discovery of more 
specimens this point must remain in doubt. 
Occurrence .—Lower Miocene (Bowden horizon): Cercado de Mao, Santo 
Domingo (rare). 
Holotype. —Cat. No. 68558, U.S.N.M. 
SCHIZOPODRELLA UNICORNIS Johnston, 1847. 
Plate 17, figs. 13, 14. 
1847. Lepralia unicornis Johnston, History of British Zoophytes, ed. 2, p. 320, pi. 57, fig. 1. 
1880. Schizoporella unicornis Hincks, British Marine Polyzoa, p. 238, pi. 35, figs. 1-5. 
1889. Schizoporella unicornis Jelly, Synonymic Catalogue of Marine Bryozoa, p. 236 (general 
bibliography). 
1904. Schizoporella subquadrata Ulrich and Bassler, Maryland Geological Survey, Miocene, p. 
420, pi. 114, fig. 1; pi. 118, figs. 5, 6. 
1906. Schizoporella unicornis Canu, Bryozoaires fossiles des Terrains du Sud-Ouest de la France, 
I Aquatanien, Bulletin de la Societe geologique de France, p. 516 (biliography). 
1907. Schizoporella unicornis Calvet, Expeditions scientifiques du Travailleur et du Talisman, 
vol. 8, p. 417 (bibliography). 
1914. Schizoporella unicornis Osburn, The Bryozoa of the Tortugas Islands, Publications Carnegie 
Institute of Washington, No. 182, p. 205 (American bibliography). 
1918. Schizoporella unicornis Waters, Marine Fauna fo the Cape Verde Islands, Linnean Society’s 
Journal Zoology, vol. 34, p. 14, pi. 2, figs. 14-17, 22 (bibliography). 
1919. Schizopodrella unicornis Canu and Bassler, Geology and Paleontology of the West Indies, 
Bryozoa, Publication of the Carnegie Institution of Washington, no. 291, p. 90. 
This species may easily be confused with Stylopoma spongites Pallas, 1766; 
it is distinguished from it by the wide, proximal sinus of its apertura and by the quite 
different form of its ovicell. 
S. unicornis is quite diffused through the European Tertiary formations, but 
on the contrary is quite rare in America, although its geologic distribution here 
appears to be almost identical. 
Occurrence .—Lower Miocene: (Bowden formation): Bowden, Jamaica (rare). 
Miocene (Choptank formation): Governor Bun, Maryland (rare). Miocene (Duplin 
12184—23—Bull. 125-S 
