REPORT ON THE FORA MINIFERA. 
489 
successively larger as the test approaches completion, but no general rule can be laid down 
in this respect. Sometimes the increase in size is confined to the earlier chambers, and 
those subsequently formed become gradually smaller, so that the shell is widest near the 
middle ; occasionally the segments preserve a uniform diameter from first to last ; and 
not unfrequently the initial segment is larger than those immediately succeeding it. The 
primordial end of the test is often mucronate. 
The segments are attached end to end, in single series, and the general contour of the test 
depends to a great degree on the extent to which the adjoining chambers are in contact 
with each other. The shape of the individual segments may be cylindrical, inflated, 
pyriform, fusiform, elliptical, or globular ; and they may either be combined like a row of 
beads with thin connecting stolons ; or more closely, with external depressions of greater 
or less depth marking the septal planes ; or so as to form a compact cylinder with the 
sutures indicated only by fine lines ; or lastly, the segments may be inequilateral and the 
sutures oblique. 
The aperture is terminal, and is usually situated in a nipple-shaped projection, or in 
a more or less produced neck ; but sometimes it is flush with the surface of the final 
segment, and in rare cases it is inverted as in the entosolenian Lagence. It takes the 
form either of a simple rounded orifice, with or without an everted lip, or of a number of 
radiating fissures ; and when simple is frequently surrounded by a radiate corona of 
superficial grooves or raised lines. 
The exterior of the test is either smooth or ornamented by the exogenous thickening 
of the wall in various ways. Longitudinal striae, continuous or interrupted costae, 
tubercles, or spines, are the more common varieties of surface-ornament. In addition to 
these, the septal lines are sometimes limbate or embossed, and the tubular neck of certain 
species is often decorated with raised annulated or spiral bands of shelly deposit. 
The genus Nodosaria was divided by d’Orbigny into five sub-genera : — I. Glandu- 
lina; II. Nodosaria , proper; III. Dentalina ; IV. Orthocerina ; V. Mucronina. 1 Of 
these Mucronina contained only a single species, differing in no important particular from 
Lingulina, and was subsequently abandoned by the author. The name Orthocerina was 
employed for a mixed group, the Nodosarine members of which are now included in Reuss’s 
genus Rhabdogonium, for reasons wdiich will appear on a later page. Of the rest, the most 
that can be said is that the term Dentalina has been used to distinguish the curved 
varieties, and Glandidina the short varieties of the genus. Employed in this way the 
terms are sometimes convenient, but in any stricter or more definite sense they have no 
zoological value. 
The immediate allies of Nodosaria are found in the genera Frondicularia, Lingulina. 
and Vaginulina, which represent respectively the compressed forms of the short, normal, 
and obliquely-septate varieties of the type. 
1 Ann. Sci. Nat., 1826, vol. vii. pp. 252-256. 
