Tertiary Foraminif era from Borneo. 259 



shown in fig. 1 of PI. X. Fig. 7 of PI. IX. sliows the 

 vertical section and fig. 8 the cliarnbers of the median pUme ; 

 while a horizontal section cntting the chambers above the 

 median plane is given in fig. 10. 



Form B. — Shell discoidal, regularly swollen at the centre; 

 surface smooth and devoid of ornament; edge thin and more 

 extended than in form A ; initial chamber invisible ; some 

 specimens appear to show a spiral arrangement of the first 

 few chambers ; chambers of the median plane lozenge-shaped 

 and similar in appearance and dimensions to the corresponding 

 chambers of form A ; chambers above and below the median 

 plane also similar to those of form A. External dimensions of 

 the shell 10 to 12 millim. in width by about 2 milhm. in 

 thickness ; some individuals may considerably exceed in size 

 the width here given, because the thin edge of the specimens 

 we have examined is generally more or less broken. The 

 chambers of the median plane of form B are shown in PI. IX. 

 fig. 11. 



Occurrence. The specimens of 0. {Lepidocychna) Ver- 

 heeki in the British Museum and in the University Museum 

 of Zoology at Cambridge were collected by Dr. Verbeek in 

 Sumatra. Dr. Verbeek's species "^ " came from the " Marne 

 pr^s d'Hilihoia, tie de Nias, c6te occidentale de Sumatra"; 

 the species " k " was obtained from the " Calcaire de Boukit 

 Ngareli ou Pouangang, k Batoumendioulour, hauts plateaux 

 de Padang, cote occidentale de Sumatra." Our Bornean 

 specimens are from pebbles found in the bed of the River 

 Malinam. 



5. Orhitoides (^Lepidocyclina) sumatrensisj Brady. 

 (PI. X. figs. 7-12.) 



Orhitoides sumatrensis, Brady, Geol. Mao;'. 1875, p. 530, pi. xiv. fig. 3 ; 

 . and Jaarb. Mijn. Ned. Ooste-Indie, 1878, vol. vii. pt. 2, pi. ii. fig. 3, 

 p. 105. 



This species was first described by Brady in the paper on 

 the Sumatran Foraminifera published in the Geol. xVlag. as 

 above. We reproduce here the material part of Brady's 

 note : — " There are still some two or three little fossils 

 pertaining to the genus Orhitoidei^. They are subglobular or 

 only slightly compressed, 3 millim. in diameter and about 

 2'5 millim. in thickness. The exterior is rough and granular. 

 Laid horizontally, there is an irregular partial extension of 

 the periphery, which seems to suggest an abortive disc. It 

 is within the bounds of possibility that these specimens may 

 be the central thick portions of some form like the more 

 umbonate varieties of 0. dispansa, but the interior structure 



