NOKTH AMERICAN LATER TERTIARY AND QUATERNARY BRYOZOA. 17 



Order CHEILOSTOMATA Busk. 



Suborder Anasca Levinsen. 



Division I. MALACOSTEGA Levinsen 



Family ELECTRINIDAE D'Orbigny, 1851. 



Genus ELECTRA Lamouroux, 1816. 



(For description, see Bulletin 106, U. S. National Museum, p. 76.) 



ELECTRA MONOSTACHYS Busk. 1854. 



Plate 29, figs. 1-3. 

 1854 Memhranipora monostnchys Busk, Catalogue marine Polyzoa in British Museum, pt. 2, Chei- 



IS5. JSrS; '^-ii B::s::'Monograph fossil Polyzoa of the Crag, Publications Pale- 



ontosraphical Society, London, vol. 14, p. 31, pi. 2, fig. 2. , ,, « q j „! is 



1880. Membmnipora monostachys HiscKS, British Marine Polyzoa, p. lol. pi. 1,, hgs. 6, 4. pi. i», 



1889. Meml'ra^pora monostachys Jelly, A Synonymic Catalogue of Marine Bryozoa, p. 155 (Cites 



1896 «mm>om mono.iac;«,s Calvet, Bryozoaires: Resultats scientifiques de la Campagne du 



" Caiulen" dans le Golfe de Gascogne, Aiinales de I'Universite de Lyon, vol. -6, p. -oJ. 

 1900. Memhranipora monostachys Waters, Bryozoa from Franz-Josef Land, Journal Linnean Society 



1904. Memhranipora inonostachys Calvet, Bryozoen: i.rgeDnisse uer riamu^.s-' — =" 



1911. SZZ!ip^aVLtac!,ys Gueui.-Gaxivet, Bryozoaires de Texpedition des Jacques 



Cartier, Bulletin de I'lnstitut oceanigraphique, no. 20/ , p. 9. 

 1912 Elecm ^nonostachys Nordoaard, Revision av Universitetsmuseets samling ar norske Brvo- 



zoer K-1 norske Videnskabers Selskabs Skriften, 1911, no. 3, pp. 1-19. 

 1912 M^mLnipora .nonostachys Osburn-, The Bryozoa of the Woods Hole Region, Bulletin Bureau 



Fisheries vol 30, 1910, p. 227, pi. 22, fig. 29; pi. 39, fig.,87. 

 1914. Jcl™ — ae..v;CA.L;,'contribution a I'etude des Bryozoaires fossUes, ^^es Bryozoaires 



du Stampien, XIV, Bulletin Soci^te Geologique de France, ser. 4, vol. 14, p. 14,, pi. 4, 



"'■'• ^ . I ?.o = 0.26-0.3-1 mm. Zooec.ia'^^'==°-^°'°-'^ ""''■ 



Measurements. ^Opesi&\ j^ ^Q.^^ ^^ Aooeria^^^ =0.24-0.26 mm. 



rark,twns.^Our specimens agree with the ligtires given by Hmoks in l^SO and 

 by Busk in 1859. The variety with large gymnocyst noted by Waters in 1900 

 probably constitutes a distinct species, perhaps identical with Membrampora arcaata 

 Canu, 1908, from the Post-Pampean of Argentina. , « „ i :„ 



This species extends scarcely beyond the Tropics and it has remained faxed m 



the Fri-id and Temperate Zones. Its occurrence in the Pliocene of South Carolina 



ndicat^s a great contraction of the ecpiatorial zone and the position o the Iropic 



of Cancer toward the thirty-third parallel. Other species confirm this phenomenon. 



There are 10 tentacles according to Waters. p^„„.,. 



(9cc»r/Y/u-e.-Pliocene (Waccamaw marl): Waccamaw River, Horry Countv, 

 South Carolina (rare). Pleistocene: Santa Barbara, California (very rare); Waies 

 Bluff near Cornfield Harbor, St. Marys County, Maryland (rare).- 



