REPORT ON THE FORAMINIFERA. 
715 
The series has since been divided by Carter into two sections, the term Tinoporus being 
retained for the Calcarina - like forms, the simpler varieties constituting a separate genus 
Gypsina. This arrangement may be accepted, but with some reservation as to name, 
inasmuch as it is by no means clear why Schultze’s term Acervulina should not take 
precedence for the latter group. 
The typical external aspect of the test of Tinoporus is that of a biconvex disk with 
radiating points or spines, the spines being placed at approximately regular intervals on 
the median line. Sometimes the test is more gibbous, occasionally nearly globular ; 
and in such cases the spines are not confined to one plane, but are projected from 
different parts of the surface. The exterior of the test is areolated or reticulated. The 
areola), which are angular and of nearly even size, but of variable shape, are bounded by 
the slightly limbate sutures of the superficial chambers ; and the surface is studded with 
raised tubercles, which are pretty evenly distributed, occupying the angles of some of the 
meshes. The marginal spines are usually from three to eight in number ; they are straight, 
and taper towards the outer extremity, which is rounded or subacute ; and they T are marked 
superficially with longitudinal furrows. 
The external features of the test yield only a partial indication of its internal 
structure. When examined by means of sections, it is found that the centre of the shell 
is occupied by a sort of nucleus, consisting of a few chambers arranged spirally on one 
plane, and that the remainder, that is to say, by far the largest part of the whole, is 
built up of a multitude of cells of slightly different form, disposed in more or less 
regular layers or tiers. The outer wall of each cell or chamber is coarsely foraminated ; 
w hil st the partitions by which they are separated consist of solid shelly plates, the 
lateral connection between the adjacent chambers being maintained by small stoloniferous 
orifices. The walls of the earlier chambers are considerably thickened, the additional 
deposit forming the commencement of the supplemental skeleton. This is subsequently 7 
developed more particularly at certain points, extending radially towards the margin, and 
eventually producing the peripheral spines ; and the whole is traversed by a system of 
branching canals similar to that of Calcarina. Interposed amongst the vertical piles 
of chambers are a number of pillars of solid shell-substance, which serve to strengthen 
the framework of the shell ; and the ends of these form the superficial tubercles already 7 
referred to. 
Taken in its restricted sense, the genus Tinoporus is represented by a single 
species. 
