530 A. V. Jennings—Orbitoidal Limestone in N. Borneo. 
crystals. The only organic body observed in the residue was a 
fragment of a hexactinellid sponge. 
The Foraminifera, so far as they can be identified with any cer- 
tainty in section, are Miliola, Nodosaria, Textularia, Globigerina, 
Amphistegina, Heterostegina, and Orbitoides. The naming of Forami- 
nifera which lie in a hard rock at all angles to the plane of 
section is unsatisfactory work at best, and I must trust to the accom- 
panying figures to justify my identifications (see Plate XIV.). 
The difficulty is still greater in the discrimination of species of 
Orbitoides, and in this case I have attempted determination only in 
the case of approximately median sections. Moreover, the study of 
this genus, comparatively simple in the days when only two types 
were recognized, has become a matter of considerable trouble since 
the researches of Dr. Giimbel! have raised the number of species to 
over twenty, necessitating in his opinion the establishment of five 
subgenera. 
OrxpiTorpEs FRoM N. Borneo. 
O. (Discocyclina) papyracea, Boubée, sp.,? Pl. XIV. Fig. 5. 
Some large forms occurring in the Silungen limestone appear to 
belong to this widely distributed and variable species, the O. Fortisit 
and O. Pratti of English writers. Dr. H. B. Brady ® has recorded it 
from Sumatra, and it is common in the Nummulitic formation of 
Scinde. 
O. (Discocyclina) ephippium, Sow. sp.,* Pl. XIV. Fig. 4a, 6. 
To this species, which has a similar structure to that of O. papyracea, 
but differs from it in its saddle-shaped curvature, I have referred 
several forms in the Silungen limestone. They are larger and 
thicker than those figured by Gtimbel from the Alpine Eocene, and 
by Dr. K .von Fritsch from Borneo,’* but not more so than the original 
type. In the several examples in the Borneo limestone the symmetry 
of the curvature, together with the absence of intermediate forms, 
prevents one from regarding them simply as abnormally grown 
individuals of O. papyracea. 'The species is well known from the 
Scinde formation. 
O. (Discocyclina) dispansa, Sow. sp.,° Pl. XIV. Fig. 6. 
Small thick lenticular forms, with large embryonic chambers and 
thick columns, corresponding to a marked surface tuberculation, seem 
to be without doubt referable to this species. The examples are 
similar in shape to those recorded by Dr. Brady from Sumatra,’ while 
those figured by Dr. K. von Fritsch from Borneo are of the variety 
with wider disc. The species is also common in the Scinde formation. 
1 Abh. d. k. bayer. Akad. Wissenschaft., Miimchen, Bd. x. Abth. 2, pp. 501- 
730, Taf. 1-4 (4to.), 1868. 
2 Bull. Soc. Géol. France, vol. ii. 1832, p. 445, 
3 Grou. Maa. Vol. II. 1875, p. 535, Pl. XIV. Fig. 1. 
4 Trans. Geol. Soc. ser. 2, vol. v. 1840, Explan. pl. 24, fig. 15. 
5 Paleontographica, 1878, Supp. iii. 
6 Op. cit. p. 327, pl. 24, figs. 15, 16. 
7 Op. cit. p. 536, pl. 14, fig. 2. 
