FORAMINIFERA OF THE KEBIMBA AECHIPELAGO. 091 



extreme tenuity. At Stn. 10 some good and fairly typical examples were found ; 

 at the remaining Stns. the individuals presented characteristics linking them with 

 B. globularis, but in their outspreading growth and thinness they were certainly 

 nearer to D. cora than to the other species. 



340. Discorbina nitida (Williamson). 



Rotaliiia nitida WilUarason, 1858, RFGB. p. 54, pi. iv. figs. 106-108. 

 Rotalia nitida Brady, 188J-, FC. pp. 627, 705. 

 Discorbina nitida Wright, 1891, SWI. p. 490. 



• „ „ Sidebottora, 1904, etc, RFD. 1908, p. 13, pi. iv. fig. 6. 



,, „ Heron-Allen & Earland, 1908, etc., SB. 1911, p. 328. 



[, „ Heron-Allen & Earland, 1913, CI. p. 121. 



11 Stations. 



Generally distributed over the area, and, as a rule, extremely trne to type and 

 presenting but little variation. Most abundant at Stns. 1 and 7, where it is small 

 but normal, and at Stn. 11, where the individuals are much larger than elsewhere in 

 the gatherings. At this Stn. also two pronounced variations were observed, both of 

 which have their origin in an excessive development of the carinated edge. In 

 one form the carina separates the successive whorls, but is flush with the surface 

 of the chambers; in the other the surface of each chamber is slightly inflated, so 

 that the carina shows as a broad depressed sutural line. 



341. Discorbina concinna Brady. 



Discorhina concinna Brady, 1884, FC. p. 646, pi. xc. figs. 7, 8. 

 „ ,, Egger, 1893, FG. p. 388, pi. xv. figs. 22-24. 



Millett, 1898, etc., FM. 1903, p. 699. 

 „ „ Chapman, 1900, FLF. p. 191. 



16 Stations. 



Very frequent and often abundant, the principal variation observed being in the 

 colour, which ranges from colourless hyaline to deep red-brown. Brady suggests 

 that his species may be only the immature or arrested stage of some better-known 

 species. In view of the extreme abundance of specimens at some of the Stns., and 

 the comparative rarity of such more advanced types as D. rosacea and D. turbo, to 

 which 1). concinna evidently is most nearly allied in structure, there does not seem 

 to be much evidence in support of Brady's suggestion. As we propose to point out 

 elsewhere, however, the small rotaline specimens of Cynibalopora hulloides, so frequent 

 at some of the Kerimba Stations, are all of a D. concinna type, the individuals, indeed, 

 when detached from the balloon-chamber, being indistinguishable from I), concinna. 

 The same observation applies to the pelagic Cymbaloporse gathered by Mr. Matthews 

 at Corney Point, S. Australia (Earland, 1902; see sub C. bulloides rei's.), and to some 

 pelagic gatherings of Ci/mbalopora made by Sir J. Murray on the ' Challenger,' which 



