FORAMINIFERA OF THE ATLANTIC OCEAN. 



61 



Description. — Test pyramidal, three-sided, triangular in transverse 

 section, the sides flat or slightly concave, the initial end acutely 

 pointed; initial end and angles of chambers often with sharp spines; 

 walls of medium thickness, hyaline, or in some cases thickened and 

 rough, perforate, smooth or granular; apertural end of test bluntly 

 angled, the edges of the chambers thickened; aperture a curved slit 

 at the base of the inner edge of the chamber. 



Length 0.25-0.75 mm. 



Distribution. — From the available records this seems to be a very 

 widely distributed species in shallow water of warm regions. It is, 

 however, known from numerous stations about the British Isles 

 according to published records. In the western Atlantic there are 

 several Challenger stations, including two off the Lesser Antilles. 

 Neither Flint or Bagg record this from the Gulf of Mexico or the Car- 

 ibbean. I have had specimens from a few Albatross stations south- 

 ward from Chesapeake Bay to Key West, and also from Montego 

 Bay, Jamaica, and one station off the coast of Brazil. It was not 

 common at any of these stations, but it was common at station 

 D2758, in 20 fathoms (37 meters), off the coast of Brazil. It seems 

 to be widely spread in the Indo-Pacific in shallow water. 



Verneuilina spinulosa — material examined. 



Genus VALVULINA d'Orbigny, 1826. 



Valvulina d'Orbigny (type, V. triangularis d'Orbigny), Ann. Sci. Nat., vol. 7, 

 1826, p. 270.— H. B. Brady, Rep. Voy. Challenger, Zoology, vol. 9, 1884, 

 p. 391.— Chapman, The Foraminifera, 1902, p. 171.— Cushman, Bull. 71, 

 U. S. Nat. Mus., pt. 2, 1911, p. 58. 



Rotalina (part) Williamson, Rec. Foram. Great Britain, 1858, p. 55. 



Description. — Test spiral, conical, with three chambers in a whorl, 

 uxnbilicate, usually attached; wall arenaceous, fairly smooth; aper- 

 ture provided with a valvular tooth; color usually reddish-brown, 

 area of fixation white or light gray. 



Species referred to this genus are recorded as far back as the Car- 

 boniferous. 



The test is typically attached, usually by a large area of fixation, 

 but specimens are often found detached. 



