56 SHALLOW-WATER FORAMINIFERA OF TORTUGAS REGION. 



retral processes small and numerous in the depressed sutural lines; umbilical 

 region depressed, but without any secondary development of shell material; 

 wall thin, translucent, fmely punctate; aperture a row of small pores at the 

 base of the apertural face of the chamber. 



Diameter usually not exceeding 0.60 mm. in the Tortugas specimens. 



D'Orbigny described this species from the shore sands of Cuba and 

 Jamaica. Some of the specimens which I have recorded from the 

 north coast of Jamaica (Proc. U. S. Nat. Mus., vol. 59, 1921, p. 62) 

 as Polystomclla cf. P. striato-punctata are undoubtedly P. poeyana. 

 This differs from the ordinary P. striato-punctata of higher latitudes. 



Polystomclla discoidalis d'Orbigny. 



(Plate 10, Figures 3, 4.) 



Polyatomella discoidalis d'Orbigny, in De la Sagra, Hist. Fis. Pol. Nat. Cuba, 1839, "Forami- 

 uif^res," p. 76, pi. 6, figs. 23, 24. 



Test equally biconvex; periphery subacute; umbilical region with a fairly 

 large boss of clear shell material projecting beyond the general contour of 

 the test; chambers numerous, 10 to 14 in the last-formed coil; the periphery 

 slightly lobulated in the last-formed portion; sutures little, if at all, depressed, 

 retral processes short and numerous ; wall translucent, with very numerous, 

 closely set punctse, the central boss clear, with a very few large punctae; 

 aperture consisting of a row of very small circular openings at the base of 

 the apertural face. 



Diameter of the Tortugas specimens up to 1 mm. 



P. discoidalis was described by d'Orbigny from shore sands of 

 Cuba and Jamaica, where it was common. Next to P. poeyana, it 

 is the most common species of the genus in the Tortugas region. 



This seems related to the much more highly developed P. craticulata 

 (Fichtel and Moll), which is especially characteristic of the East Indian 

 region. 



Polystomclla macclla (Fichtel and Moll) var. 



(Plate 10, Figures 1, 2.) 



I have referred to this species numerous specimens from the Tor- 

 tugas region which have the subacute periphery and the retral proc- 

 esses longer than the intermediate portion of the chamber, but the 

 entire test is less developed than in most specimens referred by 

 authors to this species. This may be a varietal form of P. macella, 

 or it may be a new species in this region. Similar specimens are 

 found in the warmer waters off New Zealand and elsewhere. 



The specimens which I have referred to P. crispa from the Miocene 

 of the Coastal Plain (Bull. 676, U. S. Geol. Survey, 1918, pi. 27, figs. 

 5 a, h) are probably the same as these recent ones from the Tortugas. 



Polystomclla advena, new species. 



(Plate 9, Figures 11, 12.) 



Polystomella subnodosa H. B. Brady (not Miinster), Rep. Voy. Challenger, Zoology, vol. 9, 

 1884, p. 734, pi. 110, figs. 1 a, b. — Chapman, Journ. Linn. See. London, Zoology, 

 vol. 28, 1902, p. 203. — Millett, Journ. Roy. Micr. Soc, 1904, p. 604. — Bagg, Proc. 

 U. S. Nat. Mu3., vol. 34, 1908, p. 165. — Heron-Allen and Earland, Trans. Zool. 

 Soc. London, vol. 20, 1915, p. 733. 



