MILIOLIDAE — TRILOCULINA. 73 



Triloculina oblonga (Montagu). 



Vermicidum oblongutn Montagu, Test Brit., 1803, p. 522, pi. 14, fig. 9. 



Triloculina oblonga d'Orbigny, Ann. Sci. Nat., vol. 7, 1826, p. 300, No. 16; Modeles, 1826, 

 No. 95; in De la Sagra, Hist. Fis. Pol. Nat. Cuba, 1839, "Foraminifferes," p. 17.5*, 

 pi. 10, figs. 3 to 5. — Cushman, Proc. U. S. Nat. Mus., vol. 59, 1921, p. 69, pi 17 

 figs. 5, 6. 



Specimens which may be referred to this species are common at 

 most of the stations in the collection, the most common form being 

 similar to that figured by d'Orbigny in the Cuban monograph. I 

 had specimens also from the north coast of Jamaica, and it seems 

 to be common generally in the West Indian region, and also widely 

 distributed elsewhere. 



Triloculina circularis Bornemann. 



Triloculina circularis Bornemann, Zeitschr. deutsch. geol. Ges., vol. 7. 1855, p. 349, pi. 19, 

 fig. 4.— Cushman, Bull. 71, U. S. Nat. Mus., pt. 6, 1917, p. 67, pi. 25, fig. 4; pi. 26, 

 fig. 1; figs. 33, 34 (in text); Proc. U. S. Nat. Mus., vol. 59, 1921, p. 69. 



MUiolina circularis H. B. Brady, Rep. Voy. Challenger, Zoology, vol. 9, 1884, p 169 pi 4 

 figs. 3 a to c; pi. 5, figs. 13, 14? 



Triloculina circularis is one of the most common species of the 

 genus in the collection. It is a species which is characteristic of 

 just such conditions as obtained in the Tortugas region, and is 

 widely distributed in shallow, tropical waters. It is rather surprising 

 that d'Orbigny did not describe it in his Cuban monograph, as it 

 is widely distributed in the West Indian region. The developmental 

 stages are interesting, but may always be distinguished by the large, 

 flattened, semicircular tooth, which is usually placed somewhat out 

 of the aperture itself. 



Triloculina rotunda d'Orbigny. 



Trilocuiina rotunda d'Orbigny, Ann. Sci. Nat., vol. 7, 1826. p. 299, No. 4.— Schlumberger, 

 Mem. Soc. Zool. France, vol. 6, 1893, p. 206, pi. 1, figs. 48 to 50. 



MUiolina rotunda Millett, Journ. Roy. Micr. Soc, 1898, p. 267, pi. 5, figs. 15, 16. — Side- 

 bottom, Manchester Lit. Philos. Soc, vol. 48, No. 5, 1904, p. 8. 



Test somewhat longer than wide; chambers rotund; periphery broadly 

 rounded; surface of the test made up largely or entirely of the two last-formed 

 chambers; sutures very slightly depressed; apertural end somewhat contracted, 

 with a slightly thickened lip; aperture rounded, with a single bifid tooth, pro- 

 jecting somewhat above the outline of the aperture; surface of the test smooth 

 and shining, often with transverse WTinkles. 



Length of the Tortugas specimens up to 0.80 mm. 



D'Orbigny originally had T. rotunda from the Adriatic Sea, and 

 Schlumberger also records it from the Mediterranean, in the Gulf of 

 Marseilles. Sidebottom's record is from the coast of the island of 

 Delos. Millett records and figures it from the Malay Archipelago. 

 Specimens similar to those figured by Millett have occurred at all 

 of the Tortugas stations, often in considerable numbers. Millett 

 notes that the largest specimens which he had were bilocuUne, and 

 from a study of the Tortugas collection it would seem as though the 

 species might even be better referred to Biloculina than to Triloculina. 

 The adults are usually bilocuKne, but smaller specimens still in the 

 triloculine stage are not uncommon. 



