NORTH AMERICAN LATER TERTIARY AND QUATERNARY BRYOZOA. 105 



SCHIZOPODRELLA MUTABILIS Canu and Bassler. 1919. 



Plate 6, figs. 3-5. 



1919. Schizopodrelh? mutabilk Canu and Bassler, Geology and Paleontology of the West Indies, 

 Bryozoa, Publications of the Carnegie Institution of Washington, no. 291, p. 90, pi. 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. 



^ . ^ I /ia = 0.18-0.20 mm. „ . /i2 = 0.70mm. 



Measurements. — Apertura s , „ , „ Ziooecia \ -, _ „ . 



^ I /a = 0.12 mm. U2 = 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 GemelliporelJa 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 Johnslon, 1847. 



Plate 17, figs. 13, 14. 



1847. Lepralia unicornis Joh.vston, History of British Zoophytes, ed. 2, p. 320, pi. 57, fig. 1. 



1880. Schizoporella unicornis Hinoks, 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 Soci^t^ g^ologique 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 difl'used 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 Rim, Maryland (rare) . Miocene (Duplin 

 12184— 23— Bull. 125 8 



