539 



IX.- - Report on the Recent Foraminifera of the Malay Archipelago 

 collected by Mr. A. Burr and, F.R.M.S.—Part IX. 



By Fortescue William Millett, F.B.M.S. 



(Bead 17th October, 1900.) 

 Plate IV. 



Bifarina elongata sp. n., plate IV. figs. 1, 2. 



Test elongate, straight, compressed, tapering gradually towards 

 the aboral end. The earlier chambers small and biserial or irregularly 

 agglomerated. The uniserial chambers inflated, with projecting mar- 

 gins causing the peripheral margin of the test to be tabulated ; the 

 earlier of these chambers are trilateral, the terminal ones quadri- 

 lateral. Sutures depressed. Surface ornamented with longitudinal 

 lines of puncta. Aperture a long bordered slit at the apex of the 

 chamber. Length 0*76 mm. 



There is very little variation in this interesting form. The lines 

 of perforations may be more or less distinct; and frequently a con- 

 striction of the cell- wall causes an inflated lobe to be formed at the 

 projecting base of the uniserial chambers. 



A stage in the transition from the biserial to the uniserial 

 arrangement of the chambers is well indicated in the Bolivina 

 porrecta of Brady, with its zigzag sutures and triangular chambers 

 extending the full width of the test. This is carried a step further 

 by the Malay allied examples, which in the later stages attain the 

 true uniserial plan of growth, and serve to bind the whole together 

 in a very natural group. Having thus to deal with dimorphous 

 forms derived from both Virgidina and Bolivina, it is convenient 



EXPLANATION OF PLATE IV. 



-Bifarina elongata sp. n. x 75. 



» „ i, A few of tli c uniserial chambers, x 75. 



„ porrecta, Brady sp. x 90. 

 -Bolivina nobilis Hantken. x 90. 

 „ textilarioides Reuss. x 90. 

 ,, convallaria sp. n. x 100. 

 „ Durrandii sp. n. x 100. 



„ Karreriana Brady var. carinata var. n. x 60.. 

 „ Hantkeniana Brady, x 55. 

 „ Scliwagtriana Brady. X 65. 

 -Mimosina affinis sp. n. x 90. 

 „ spinulosa sp. n. x 75. 

 „ „ „ var. x 90. 



„ hystrix sp. n. X 75. 



„ „ a portion of the cell-wall mounted iu balsam and viewed 



by transmitted light, x 180. 



2 o 2 



