62 BULLETIN 11, UNITED STATES NATIONAL MUSEUM. 



Genus TRIPLASIA Reuss, 1854. 



Vaginulina d'Orbigny (part), Ann. Sci. Nat., vol. 7, 1826, p. 258. 

 Orthocerina d'Okbigny (part) in De la Sagra, Hist. Fis. Pol. Nat., Cuba, 1839, 



"Foraminiferes," p. 18. 

 Triplasia Reuss, Denkschr. Akad. Wiss. Wien, vol. 7, abth. 1, 1854, p. 65. 

 Rhabdogonium Reuss, Sitz. Akad. Wiss. Wien, vol. 40, 1860, p. 198. — H. B. 



Brady, Rep. Voy. Challenger, Zoology, vol. 9, 1884; p. 524. 



Description. — Test elongate, triangular or quadrangular in cross 

 section, chambers numerous, uniserial or somewhat irregular; wall 

 hyaline, surface smooth or roughened, aperture at the end of a short 

 tubular neck. 



There has been some dispute as to the names for this genus. 

 D'Orbigny applied the name Vaginulina to a species of this genus, 

 but as this name had been used previously in a different sense it is not 

 available here. He also described Orthocerina, but the original spe- 

 cies described under this genus is probably a Clavulina as nearly as 

 can be determined. Therefore it can not be used here. The next 

 name, Triplasia, was used by Reuss for three-angled species. Rhab- 

 dogonium was a later name which he used because four-angled species 

 had been found and Reuss thought Rhabdogonium a more appropriate 

 name. He put Triplasia as a synonym of Rhabdogonium and places 

 there his type species of Triplasia {Triplasia murchisonii) . As a 

 result it seems that Triplasia must, by all laws of priority, be used 

 instead of Rhabdogonium. 



TRIPLASIA TRICARINATA (d'Orbigny). 

 Plate 39, fig. 2. 



Vaginulina tricarinata d'Orbigny, Ann. Sci. Nat., vol. 7, 1826, p. 258 No. 4; 

 Modeles, No. 4. 



Rhabdogonium tricarinatum H. B. Brady, Rep. Voy. Challenger, Zoology, vol. 9, 

 1884, p. 525, pi. 67, fig. 1-3. — Sherborn and Chapman, Journ. Roy. Micr. 

 Soc, 1886, p. 752, pi. 15, fig. 16. — H. B. Brady, Parker, and Jones, Trans. 

 Zool. Soc. London, vol. 12, 1888, p. 223, pi. 45, fig. 3.— Schrodt, Zeitschr. 

 deutsch. geol. Ges., vol. 42, 1890, p. 411, pi. 22, fig. 2.— Burrows, Sher- 

 born, and Bailey, Journ. Roy. Micr. Soc, 1890, p. 558, pi. 10, fig. 7. — 

 Wright, Proc. Roy. Irish Acad., ser. 3, vol. 1, 1891, p. 484. — Egger, Abh. 

 kon. bay. Akad. Wiss. Munchen, CI. u, vol. 18, 1893, p. 355, pi. 11, figs. 49, 50; 

 pi. 12, figs. 36-38.— Chapman, Proc. Zool. Soc, London, 1895, p. 33— Sil- 

 vestri, Mem. Pont. Accad. Nuovi Lincei, vol. 12, 1896, p. 194, pi. 1, fig. 8. — 

 Millett, Journ. Micr. Soc, 1902, p. 525.— Bagg, Proc. U. S. Nat. Mus., 

 vol. 34, 1908, p. 145. 



Description. — Test elongate, slightly tapering toward either end, 

 often somewhat twisted, triangular in cross section, aperture in the 

 center at the end of the chamber, usually with a short tubular neck 

 and phialine lip ; angles of the test carinate. 



Length about 0.4 mm. 



