88 



"blunter and more obtuse point than is usual in typical examples; 

 whilst, on the other hand, B. digitata^ in the Hergott material, 

 is often of the same colour as B. nodosaria, and approaches 

 more nearly that species in outline.* 



The genus Bigenerina is a very ancient one, if Mr. 

 Brady's Carboniferous species, B. pcttula, belongs to this genus. 

 Dr. Dawson has also fi^^ured what appears to be the same 

 species from the Laurentian of Canada, and is there associated 

 with the much-disputed Eozoon Canadense. The genus is not 

 met with in the Secondary rocks, and the two species to which 

 the Hergott examples are referred make their first appearance, 

 so far as hitherto known, B. nodosaria in the Miocene of 

 A^ienna and Malta, and B. digitata in the later Tertiaries of 

 Italy. The distribution of these species in existing seas is 

 T5omewhat restricted. B. nodosaria is common in the IS'ortli 

 Atlantic, where it occupies shallow water ; it is mucli rarer in 

 the Mediterranean and North Pacific, but in the southern 

 hemisphere Mr. Brady describes it as " exceedingly rare," 

 being only found at one point in the South Atlantic. B. digi- 

 tata is only known as a European form. The examples in the 

 Hergott beds would imply that these species have had a much 

 wider range in geological times than exists at the present day. 

 Two examples, unfortunately broken, of a much coarser and 

 more robust species of Bigenerina were found in one sample of 

 material from Hergott, but these are too imperfect specimens 

 to be dealt with at present. 



Gnudryina pupoides, d'Orb. — The genus Gaiidri/ina compre- 

 hends another dimorphous form of the Foraminifera, in which 

 the earlier chambers follow a triserial arrangement and then 

 pass in their later growth into a biserial order. Its geological 

 history begins with the Cretaceous period, and it is found in 

 most later formations to the present day. The examples from 

 Hergott belong to two species. The most characteristic and 

 plentiful of these species, we have referred to G. piqmides, as 

 it possesses in common with that species large and inflated 

 chambers towards the oral extremity, whilst it tapers rapidly 

 towards the primordial end, is finely arenaceous in texture, 

 and possesses a projecting terminal orifice similar to 

 G. siplwnelJa. These examples are all more or less flattened, 

 which renders determination the more diflicult, but they can 

 very well be classed with G.pupoides until better specimens are 

 found to disprove this relationship. In existing seas this 

 species is common in deep water, and occurs in the Challenger 

 gatherings from all parts of the world. It is known as far 



* I have more recently obtained very characteristic examples of B. digi- 

 tata from the Tarkauiuna Bore, which is in the same geological formation. 



