REPORT OF THE DIRECTOR I918 I75 



Polymorphina compressa d'Orbigny? 



Plate 4, figures 3a, b 

 Polymorphina compressa, d'Orbigny 1846, Foram. Foss. Vienne, 



p. 233, pi. xii, figs. 32-34 

 Polymorphina acuta d'Orbigny, 1846, Foram. Foss. Vienne, p. 234, 



pi. xiii, figs. 4, 5 and pi. xiv, figs. 5-7 

 Polymorphina compressa Parker & Jones, 1 865, Phil. Trans., 



p. 361, pi. xiii, figs. 47-51 



The few short, biserial (somewhat irregular) forms such as appear 

 on sHde i are doubtfully placed under this genus. Polymorphinae 

 are not abundant in the chert sections and it is not impossible for 

 us to be mistaken in confusing this genus with short and diagonally 

 cut Bolivinae or Virgulinae types. There is, however, in the above 

 section a strongly lobed margin and more globose segments than 

 in the above genera, and we are therefore placing this form with 

 Polymorphina. The specimen is not very distinct, and the segments 

 are rapidly converging as would be the case in a compressed type; 

 this feature requires continued focusing to bring the structure into 

 view. There are four and five segments visible in each series and 

 the length approximates o. 10 mm. 



The specimen of what appears to be Polymorphina 

 gibba on this same slide, is much larger and measures 0.25 

 mm, but the complete form is not seen. P. compressa is 

 often regarded as an elongate variety of P. lactea, but the 

 two are quite distinct and easily distinguished when typical speci- 

 mens are examined. 



This species is supposed to be represented by casts in the Silurian 

 (Ehrenberg) ; but it first becomes frequent in Mesozoic strata, 

 and is rather a cosmopolitan form in existing oceans. Parker & 

 Brady's forms were from the Arctic ocean. " 



Polymorphina gibba d'Orbigny 



Plate 4, figures 4, S 



Globulina gibba d'Orbigny, 1826, Ann. Sci. Nat., 7:266, no. 20 

 Globulina gibba d'Orbigny, 1846, Foram. Foss. Vienne, p. 227, 

 pi. xiii, figs. 13, 14 



A cross section on slide i (also slide 6) resembles closely 

 Polymorphina gibba d'Orbigny. One side of the form 

 on the lower border is broken away by a fissure in the slide; but 

 it seems likely that the interior initial chamber was connected 



