PORAMINIFEEA OF THE KERIMBA ARCHIPELAGO. 589 



the final convolution. Specimens with four chambers visible in the final convolution 

 are of very rare occurrence. 



At most of the Stns. all the larger specimens and most of the smaller ones are 

 typically milioline in the texture of their shells, but at some Stns., notably Stns. 3 

 and 10, all the individuals have walls of such extreme tenuity that they are of a 

 delicate blue opalescent tint. The H. complanata figured and described by Dakin 

 as a new species (D. 1906, FC. p. 231, fig. 7) would appear to be no more than one of 

 these thin compressed shells, with an abnormally large number of visible chambers. 

 At Stn. 4 H. compressa is represented by large and very thick-walled specimens with 

 embracing chambers, closely approaching H. circinata. A specimen was found at one 

 of the Stns., which we are figuring elsewhere (H.-A., 1915, RPF. pi. xv. fig. 31), in 

 which the hauerine shell is followed by a peneropline extension. 



100. Hauerina circinata Brady. 



Hauerina circinata Brady, 1879, etc., RRC. 1881, p. 47. 



Brady, 1884, FC. p. 191, pi. xi. figs. 14-16. 

 Rliumbler, 1906, FLC. p. 52, pi. iii. fig. 40. 



5 Stations. 



Brady separates H. circinata from H. compressa by its " more regularly nautiloid 

 form, the larger number of chambers in each circuit and its embracing segments, and 

 their diaphanous shell." He does not refer to another feature, which, however, is 

 clearly indicated in Hollick's figure, and which we think is, if anything, a more distinctive 

 feature, viz. the markings at the septa on the produced edge of the septal lines. 

 These markings, which bear some superficial resemblance to the retral processes of 

 Polystomella, indicate the position of the cribrate aperture of each chamber inside the 

 shell. They are never visible in II. compressa, but nearly always in H. circinata, 

 however thick and robust the shell may be. 



Apart from these features, it seems very doubtful whether //. circinata can be 

 regarded as anything more than an advanced growth-stage of H. compressa. At 

 Kerimba the specimens of //. circinata are confined to a relatively small number of 

 Stns. The best specimens were observed at Stns. 9 and 11 ; at Stn. 3 they were 

 extremely translucent, as was the case at this Stn. with H. compressa. At Stn. 4 the 

 shells were all thick and stoutly built. Speaking generally, similar variations occur in 

 these two so-called species at comparatively adjacent Stns., which probably confirms 

 the near relationship of the two forms. The number of chambers, which Brady makes 

 a specific feature, is not always in excess of the chambers of //. compressa from the 

 same locality. The embracing character of the chambers in the final whorl is the only 

 invariable feature separating the two forms. 



