REPORT OF THE DIRECTOR I918 177 



Orbulina ovalis Matthew 



Plate 4, figures 6, 7 



Orbulina ovalis Matthew, 1893, Trans. N. Y. Acad. Sci., 12:112, 



pi. I, fig. 20 



Orbulina ovalis Matthew, 1895, Trans. N. Y. Acad. Sci., 14:110, 



pi. I, fig. 2 , 



Orbulina universaof existing oceans is always spherical 

 anl normally built of a single chamber. There are occasionally 

 met with double-chambered types in which the segments are ingrown 

 and not bilobed, as inGlobigerina bilobata, which 

 never exhibit this sphericity. Such elongation as these types exhibit 

 may belong to the species figured by Matthew as Orbulina 

 ovalis. It is not altogether certain that the few elongated 

 and apparently unicelled Foraminifera, such as are seen on slide i, 

 really belong here; but it seems probable that they do. There is 

 a very peculiar and irregular distribution of minute circles seen 

 in the cross section of one form shown on this slide, and if these 

 represent chambers our determination is erroneous. In any case, 

 however, oval types are observed which seem to belong to the above 

 species and which may perhaps be allowed to stand. 



Orbulina porosa Terquem 



Plate 4, figures 8, 9 



Globulina porosa Terquem, 1858, Foram. Lias, ist Mem., p. 633 

 Orbulina liasica Terquem, 1862, Foram. Lias, 2d Mem., p. 432, 



pi. V, fig. 4 

 Orbulina porosa Vadasz, 1910, Triasforam. aus dem Balcony, p. 29, 



pi. I, fig. 30 (errata for 31) 



This species of Orbulina differs from 0. universa, the 

 common, unicellar, globigerine type, in the coarseness of its 

 pores and the asperate surface. In fossil form it appears in cross 

 section as a roughened, crenulation-like surface, exceedingly minute; 

 but it seems to be sufficiently distinct to be recognized in some 

 forms on slide 6. It is rather larger than 0. universa, 

 although this is a minor factor in its identification. The specimen 

 referred to has a diameter of 0.17 mm. 



The species seems to have been not infrequent in a number of 

 early Mesozoic horizons; but is an exceedingly rare type today, 

 and we have never identified it in existing oceans. The Challenger 

 reported the type from several stations, one in the North Atlantic 

 at 1750 fathoms and another at 1485. 



