4 FORAMINIFERA OF THE CRAG. 
type) layers of chambers. Pseudopodial orifices situated in depressions on the lateral face 
of the external annular chamber. In the simple type, consisting of a single row of pores, 
there is one pore in each depression; in the complex type several rows, roughly corre- 
sponding to the number of layers of chambers. Diameter, ;,th inch to 1 inch. 
As the variations from the typical form are so unimportant that subdivision 
is unnecessary, little need be added in respect to the species, not already given in the 
generic distinctions. Ehrenberg rightly referred his “ Sordtes” (a simple Orbitolite) to 
the WV. orbiculus, of Forskal, whose description of it embraces also “ Amphisorus” (com- 
plex in growth). 
We have seen but one or two perfect specimens of Orébztolites orbiculus from the 
Crag (Sutton), and these have been imbedded in a hard matrix ; but we have a few fragments 
separated from the rock. Our figure, Plate III, fig. 45, is taken from one of these frag- 
ments ; and figures 46 and 47 illustrate the structure of the complex type, the one being 
a view of a portion of the edge of a specimen, showing the pseudopodial apertures ; the 
other a vertical section, exhibiting the arrangement of the chambers, and their connection 
with each other. 
The distribution of Oréztolites is almost confined to tropical latitudes, its range 
extending but little into the seas of the temperate zones. On the Australian shores, in the 
Indian Ocean, and in the Caribbean and Red Seas, it is, perhaps, most abundant. It 
exists in the Mediterranean. Fossil specimens are first found in the Maestricht Beds 
(O. macropora), and it reaches its maximum abundance in the Calcaire grossier of the 
Paris Basin. It is also found in the Bracklesham beds of Hampshire. 
ALVEOLINA, Sp. 
We may notice, in passing, the occurrence of one or two somewhat obscure specimens 
of Alveolina that we found in the Bryozoan Crag of Sudbourne. They have been un- 
fortunately lost. These were so worn and devoid of character as scarcely to admit of 
specific determination ; their presence, however, is of interest in connection with that of 
some other species which may have been derived from earlier Tertiary formations. 
