48 



BULLETIN 104, UNITED STATES NATIONAL MUSEUM 



ARCHAIAS COMPRESSUS (d'Orbigny) 



Plate 17, figures 1, 2 



Orbiculina compressa d'Orbigny, in De la Sagra, Hist. Fis. Pol. Nat. Cuba, 

 1839, " Foraminiferes," p. 73, pi. 8, figs, 4-7. — Cushman, Proc. U. S. 

 Nat. Mus., vol. 59, 1919, p. 76, pi. 19, figs. 4-6; Publ. 291, Carnegie 

 Instit. Washington, 1919, p. 70, pi. 7, fig. 6; Publ. 311, 1922, p. 81; Publ. 

 344, 1926, p. 84. 



Test circular in outline, the early portion with several layers of 

 chamberlets and the chambers much thicker than in later growth 

 which is annular and the chamberlets in a single or double layer, 

 greatest thickness of the test formed by the earher involute portion; 

 wall calcareous, imperforate, except in the proloculum and second 

 chamber; aperture in the adult formed by a marginal row of pores, 

 either single or double. 



Diameter up to 2.50 mm. 



The original material described by d'Orbigny came from the West 

 Indies and was recorded as rare in Cuba, more common at Guadeloupe 

 and St. Thomas, but abundant in Jamaica. It has occurred fossil 

 in the Late Tertiary of Jamaica, Florida, and Panama. 



It is not the same as Sorites marginalis Lamarck and can be dis- 

 tinguished from that species especially by the thickening of the 

 earlier portion. A discussion of this species has already been given * 

 with the early stages in development. 



This species has often been included with Archaias angulatus 

 but the two are distinct. A. angulatus, as shown in the figures of 

 that species, does not become completely annular and is a much 

 thicker, heavier species. 



Archaias compressus — Material examined 



• Bull. 71, U. S. Nat. Mus., pt. 6, pp. 1917, 89-91. 



