FORAMINIFERA OF THE ATLANTIC OCEAN. 37 



LAGENA MARGINATA (Walker and Boys), variety. 



Plate S, fig. 1. 



Description. — Variety differing from the typical in the very sliglit 

 thin keel extending entirely about the test, the aperture very elong- 

 ate, elliptical. 



Diameter up to 1 mm. or slightly more. 



Distrihntion. — In the Gulf of Mexico and the Caribbean there is 

 a large form with a very broad thin transparent keel which may 

 possibly be a variety of Lagena marginata^ but further study may 

 show it to be a distinct species. 



Lagena niarginata, var. — material examined. 



LAGENA MARGINATO-PERFORATA Seguenza. 



Plate 7, fig. 4. 



Lagena marginato-perforata Seguenza, Atti Accad. Lincei, ser. 3, vol. 6, 

 18S0, p. 332, pi. 17, fig. 34. — Sidehottom, Mem. Proc. Manchester Lit. 

 Philos. Soc, vol. 50, No. 5, 1906, p. 10, pi. 2, fig. 5; vol. 54, No. 16, 

 1910, p. IS. — Heron-Allen and Eauland, Proc. Roy. Irish Acad., vol. 

 31, pt. 64, 1913, p. 86, pi. 7, figs. 5, 6; Trans. Zool. Soc. London, vol. 

 20, 1915, p. 663 ; Trans. Linn. Soc. Ivondon, ser. 2, vol. 11, 191G, p. 252 ; 

 Journ. Roy. Micr. Soc, 1916, p. 46. 



" This species occurs at 9 stations among the dredgings and is 

 quite common in the fine mud of Station 13. There is considerable 

 variety in the specimens, some having a single keel, the true L. 

 marginato-perforata, others a double keel (= Fissurina punctatrt 

 (Seguenza)) ; while many of the specimens are ornamented with a 

 varying number of minute radiating costae at the two extremities of 

 the shell, which, however, are not produced over the central area 

 of the test. There is usually an attached entosolenian tube, and the 

 coarse perforations from which the species takes its name are gen- 

 erally suppressed in the area of the shell where the tube is attached. 

 This agrees wdth Mr. Sidebottom's specimen and drawing; but in 

 his specimens the internal tube is described as being straight and 

 free. The species is of fairly common occurrence in shallow- water 

 tropical gatherings. Mr. Wright has recently described and iigured 



