FORAMINIFERA OF THE ATLANTIC OCEAN 51 



Test with the early chambers quinqueloculine or triloculine, later 

 ones in a rectilinear series; aperture in the adult a rounded, usually 

 elliptical opening, at the end of a short neck with a phialine hp. 



Lower Eocene to Recent. 



This genus has developed from a quinqueloculine ancestry by the 

 addition of a uniserial stage which is only represented by one or two 

 chambers in some species but in others these become numerous. 



ARTICULINA SAGRA d'Orbigny 



Plate 11, Figure 7 



Articulina sagra d'Orbigny, in De la Sagra, Hist. Fis. Pol. Nat. Cuba, 1839, 

 "Foraminiferes," p. 160, pi. 9, figs. 23-26.— Cushman, Proc. U. S. Nat. 

 Mus., vol. 59, 1921, p. 73, pi. 18, figs. 2-5; Publ. 311, Carnegie Instit. Wash- 

 ington, 1922, p. 70; Publ. 344, 1926, p. 82. 



Test elongate, composed of two portions, the earlier triloculine, the 

 later uniserial, the trilocuhne portion generally elliptical, with a 

 rounded periphery and longitudinal costae, the uniserial portion con- 

 sisting of from one to three chambers, each broader than the preced- 

 ing, transverse section circular or broadly elHptical; the aperture 

 the broadest portion of the test, with an everted lip; the wall of the 

 chamber longitudinally costate. 



Length, 1 mm.; breadth, 0.20 mm.; thickness, 0.15 mm. 



The species was originally described by d'Orbigny from Cuba, 

 Jamaica, and Martinique. It is widely distributed in the shallow 

 water, coral-reef regions of the West Indies. I have recorded it from 

 Jamaica, Porto Rico, and the Tortugas. 



ARTICULINA MEXICANA Cushman 



Plate 12, Figures 2, 3 



Vertebralina species Cushman, Proc. U. S. Nat. Mus., vol. 59, 1921, p. 64. 

 Articulina mexicana Cushman, Publ. 311, Carnegie Instit. Washington, 1922, 

 p. 70, pi. 11, figs. 7,8. 



Test somewhat compressed, generally rounded, the last-formed coil 

 composed of two to three chambers; sutures somewhat indistinct, the 

 single, uniserial chamber in the adult somewhat more compressed 

 toward the apertural end, which has a somewhat everted lip, but 

 extending only slightly beyond the general outline of the chamber; 

 surface smooth ^ shining. 



Lenc'th, 1.10 mm.; breadth, 0.95 mm.; thickness, 0.35 mm. 



This smooth species is probably widely distributed m the West 

 Indian region. I have recorded it only from Jamaica and the Tortugas 

 region, but it is to be looked for elsewhere. 



The test is thick and usually smooth and polished, but occasionally 

 as in one of the figured specimens there are traces of costae Unisonal 

 chambers are unusual, but the typical lip is strongly developed. 



