465 
bers are grouped in circles. The tangential diameter of these 
first rounds of peripheric chambers is larger than the radiary one 
(comp. VerBeeK 1896, pl. 10 f. 157). The columns are here a little 
thicker (100—180 u) than with the forms described above; they 
show both in a transversal and in a longitudinal section a very 
distinct, fibrous structure. The lumen of the lateral chambers is in 
a vertical direction very wide and their horizontal parietes are 
very thin. 
From the finding-place N°. 167 a I received likewise a specimen 
of O. javana. 
Orthophragmina dispansa Sowerby. 
Syn. O. dispansa Sow. in von Fritscu 1879? 
Q. dispansa Sow. in VerBEEK 1892 and 1896. 
O. dispansa Sow. in Martin 1881 (partim) and 1887. 
QO. dispansa Sow. in Dovvit1# 1912. 
The rock N°. 16 is entirely filled up with Orbitoids which, by 
disintregation, are partly laid bare, so that their exterior habitus 
can be studied. The maximal diameter amounts to 9 mm, the height 
to 3 mm. The fossils are considerably thickened in the centre, 
whilst at the periphery they have an excessively thin edge. The 
surface is strongly granulated; the granulae however are not sym- 
metrically divided over the whole surface. They are largest on the 
central tubercle (100—190u), towards the periphery they become 
very small, but on the very thin edge again larger granulae are 
perceptible. 
Though in general the granulae are separated by a single row of 
spacious lateral chambers, it often occurs that there are two rows 
of chambers between them. 
In sections only macrespheric individuals were found. The dimi- 
nutive size and the spacious lateral chambers make this form corre- 
spond entirely to QO. dispansa Sow, as DouvirLé described them a 
short time ago (1912). 
Rare specimens of Calcarina and little Nummulites are found in 
the limestone N°. 238, together with these Orthophragmina, whilst 
it is by no means impossible that still another very thin Orthophrag- 
mina is met with: the material was however insufficient to decide 
in this respect. 
o1 
Proceedings Royal Acad. Amsterdam. Vol. XIV, 
