132 



BULLETIN 104, UNITED STATES NATIONAL MUSEUM. 



MARGINUUNA COSTATA (Batsch). 



Plate 37, fig. 2. 



Nautilus (Orthoceras) costatus Batsch, Conch, des Seesandes, 1791, 

 p. 2, pi. 1, figs. 1 a-g. 



Margitiulina costata Buady, Rep. Roy. Challemjer, Zoology, vol. 9, 1884, 

 p. 528, pi. 65, figs. 10-13 ( ? ) .— Balkwill and Wright, Trans. Roy. 

 Irish Acad., vol. 28, 1885, p. 344.— Pearcey, Trans. Glasgow Nat. Hist. 

 Soc, vol. 2, 1890, p. 178. — Wright, Proc. Roy. Irish Acad., ser. 3, voL 

 1, 1891, p. 485. — Egger, Abh. kon. bay. Akad. Wiss. Miinchen, CI. II, 

 vol. 18, 1893, p. 347, pi. 11, fig. 19.— Heron-Allen and Earland, Proc. 

 Roy, Irish Acad., vol. 31, pt. 64, 1913, p. 98 ; Trans. Linn. Soc. London, 

 ser. 2, vol. 11, 1916, p. 261 ; Journ. Roy. Micr. Soc, 1916, p. 47. 



I have given above the references to Atlantic material recorded 

 under this name. There is evidently a difference in that found off^ 

 the British Isles and the species found in the West Indies of which 

 I have but a single specimen. Many different things have been re- 

 ferred to this specific name, and until a study can be made of the 

 forms recorded from various regions the whole complex is in a very 

 unsatisfactory state. 



Marginulina costata — material examined. 



Genus VAGINULINA D'Orbigny, 1826. 



Vaginulina D'Orbigny (type, V. legumen Linnaeus), Ann. Sci. Nat, vol. 

 7, 1826, p. 257.— H. B. Brady, Rep. Voy. Challenger, Zoology, vol. 9, 

 1884, p. 529.— Chapman, The Foraminifera, 1902, p. 192.— Cushman, 

 Bull. 71, U. S. Nat. Mus., pt. 3, 1913, p. 80. 



Description. — Test elongate ; chambers in a linear series, placed so 

 that the sutures are oblique; aperture marginal; chambers laterally 

 compressed. 



The species of Vaginulina are undoubtedly derived from coiled 

 forms, such as Cnstellaria. Most of the fossil forms are compressed 

 and very different from the recent species usually placed under this 

 genus. The aperture usually is kept at the margin of the test, and 

 tlie sutures oblique throughout. 



It reaches its greatest development in the Mesozoic. Its geological 

 history evidently ranges from the Lias to the present time. 



