FOEAMINIFEEA OF THE KERIMBA ARCHIPELAGO. 565 



43. Miliolina durrandii Millett. (Pi. XLll. figs. 11-16.) 



MilioUna durrandii Millett, 1898, etc., FM. 1898, p. 268, pi. vi. figs. 7-10. 



9 Stations. 



Generally distributed and often quite common, the finest specimens at Stns. 5, 6, 

 and 7, where it was abundant. There is a certain amount of variation in this species, 

 especially in the degree of development of the keel, but none of the costate specimens 

 referred to and described by Millett occur at Kerimba. The development of the 

 keel appears to be dependent on the stage of growth, the younger shells having 

 a much more rounded edge than the older ones, a feature that is particularly noticeable 

 in the smallest specimens, in which the keel is almost entirely absent, except near the 

 aperture. In very young shells there is a rapid increase in the length of the chamber, 

 with the result that the ultimate chamber is often more than double the entire length 

 of the preceding chamber. 



M. durrandii is one of the species first recorded from the Malay Seas by Millett, 

 but it is probably very widely distributed in shallow tropical waters. We have records 

 from the coasts of Burmah, Queensland, Java, and Macassar in the eastern seas, and 

 in the Pacific it is very abundant and typical at Tahiti. Owing to the absence of any 

 tooth to the aperture, the internal arrangement of the shell is strikingly monothalamous 

 or cornuspirine. This internal arrangement is quite similar to that described and 

 figured by Schulze in his Sj)iroloGulina hyalina (S. 1874, etc., R. no. 3, 1875, p. 132, 

 pi. vi. figs. 14-16), and is clearly brought out in Millett's fig. 10. We have 

 specimens (which are being figured elsewhere) showing ingested diatoms and small 

 specimens of other foraminifera (H-A. 1915, RPF. p. 232, pi. xiv. figs. 5, 6). 



44. Miliolina rupertiana Brady. 



Miliolina rupertiana Brady, 1879, etc., EEC. 1881, p. 46. 



„ „ Brady, 1884, FC. p. 178, pi. vii. figs. 7-12 and text-fig. 



Millett, 1898, etc., FM. 1898, p. 269, pi. vi. fig. 13. 



10 Stations. 



This highly specialised type is generally distributed over the area and fairly 

 plentiful at some of the Stns., notably Stns. 1 and 13. The specimens often attain 

 a very large size, and, as a rule, are of a narrower and more inflated type than that 

 figured by Brady, the marginal edge being at most of the Stns. quite round and smooth, 

 thus more nearly resembling Millett's figure. At several Stns., however, specimens 

 were found exhibiting a tendency to a compressed and carinate form, Avhich was, in 

 a few instances, quite as strongly developed as in Brady's figs. 7 and 9. M. rupertiana 

 is extremely common at Perim in the Red Sea. It also occurs in the Torres Straits 

 and on the Queensland coast. Brady records it as plentiful from Madagascar. 



