38 SHALLOW-WATER FORAMINIFERA OF TORTUGAS REGION. 



more or less regularly in oblique lines, giving a very different appear- 

 ance to the surface of the test than the typical form of the species. 



Genus DISCORBIS Lamarck, 1804. 



The genus Discorbis Lamarck, which has been more often used 

 under the name Discorbina of Parker and Jones, has evidently a 

 large number of species with probably well-defined faunal limi- 

 tations. A study of shallow-water material from almost any region 

 shows a considerable number of such species, and the Tortugas 

 region is no exception. There are here developed several species 

 which are very distinct from one another and in which the amount 

 of variation is not great. A comparison of these with certain of 

 the original figures given by Brady, based presumably on the spec- 

 imens from the Indo-Pacific, shows very close relations. However, 

 a comparison of Brady's figures with those of the original author's 

 in most cases shows a very decided discrepancy. The Challenger 

 figures are excellent and in using them for comparison it is possible 

 to refer some of the Tortugas species to the groups represented by 

 the Challenger figures. If, however, an attempt is made to trace 

 back the names assigned by Brady to these figures difficulties are 

 at once encountered. It is evident that in the Gulf of Mexico and 

 in the Caribbean certain species are developed which are close to 

 if not identical with the species from the warmer parts of the Pacific. 

 Most later authors have followed the disposition of these species 

 given in the Challenger report and in certain cases there seem to 

 be no specific names available for the particular species found in 

 this collection; as such, new names necessarily had to be applied. 

 Heron-Allen and Earland, in their Clare Island Survey paper, have 

 dealt with many of the species which can be referred to this genus 

 and have given a number of excellent figures of the specimens from 

 that region. Comparison of their figures with specimens from the 

 Tortugas region shows very little in common between the two 

 groups, as might be expected from the varying conditions and 

 different faunal relations of these widely separated localities. Little 

 is to be gained by using a very few names to cover widely divergent 

 forms, and a considerable increase in names used by Heron-Allen 

 and Earland is really a step toward precise work, rather than 

 towards complexity. 



Discorbis orbicularis (Terquem)? 



(Plate 5, Figure 10.) 



Rosalina orbicularis Terquem, Anim. sur la Plage de Dunkerque, 1876, p. 75, pi. 9, figs. 4 a, b. 

 Discorbis orbicularis Berthelin, Foram. de Borgneuf et Pomichet, 1878, p. 39, No. 63. — 



Cushman, Bull. 71, U. S. Nat. Mus., pt. 5. 1915. p. 16, pi. 11, fig. 1; fig. 18 (in text); 



Proc. U. S. Nat. Mus., vol. 59, 1921, p. 60. 

 Discorbina orbicularis H. B. Brady, Rep. Voy. ChaUenger, Zoology, vol. 9, 1884, p. 647, pi. 



88, figs. 4 to 8. 



