REPORT OjST THE FORAMINTFERA. 
393 
more easily detached, and specimens in the adherent condition are not very frequently 
met with. The accumulation of sand surrounding adherent specimens has already been 
described in connection with the allied form. 
Valvulina fuscci is a common North Atlantic Foraminifer. It most affects compara- 
tively shallow water, though it has been taken at depths as great as 500 or 600 
fathoms. It occurs on the shores of Norway, Great Britain, Belgium, and France, the 
Canary Islands, the Azores, and the West Indies. I have no record of its presence in the 
South Atlantic ; but in the South Pacific it has been observed at five localities, the 
depths ranging from 7 to 410 fathoms ; and in the North Pacific at a single point, 
off the Philippine Islands, 95 fathoms. The species is not known in the fossil condition. 
Clavulina, d’Orbigny. 
Spirolinites, pars, Lamarck [1804], 
Nodosaria, pars, Lamarck [1816], d’Orbigny, Morris. 
Clavulina, d’Orbiguy [1826], Munster, Bronn, Reuss, Costa, Karrer, Seguenza, Stache, Sckwager, 
Giimbel, Hantken, &c. 
Orthocerina, d’Orbigny [1826]. 
Verneuilina, pars, Parker and Jones [1860], Vanden Broeck. 
Valvulina, pars, Parker, Jones, and Brady [1865]. 
The genus Clavulina bears precisely the same relation to Valvulina that Bigenerina 
bears to Textularia ; that is to say, it is a dimorphous modification, the earlier segments 
of which are arranged in the typical manner as a triserial spire, whilst the later 
chambers are disposed in a single Nodosariform line. In recent specimens the rela- 
tionship to Valvulina may almost invariably be recognised by the aperture, which, even 
in the dimorphous varieties, retains the normal character, and is partially closed by a 
projecting tongue or valve. 
Two other genera of Textularidoe, namely, Chrysalidina and Tritaxia, have dimor- 
phous modifications resembling Clavulince ; and though there are minor differences by 
which such forms may be distinguished, the nature of the aperture affords as a rule the 
safest means of identification. Thus in Chrysalidina the aperture consists of a number 
of small pores, in Tritaxia it is a simple rounded opening, and in Clavulina it is a 
circular orifice with an overhanging valvular tougue. 
The walls of the test are thick and finely arenaceous, as shown in the various sectional 
drawings in Plate XLYIII., the constituent sand-grains being often almost entirely 
calcareous. Less frequently the test is composed of coarse sand, and presents a rough 
exterior. Sometimes a more or less complete shelly lining may be traced, and the rim 
surrounding the orifice is nearly always of fine homogeneous texture and smoothly finished. 
In the northern hemisphere the distribution of the genus Clavulina is somewhat 
limited, and does not extend much to the north of lat. 40° N., either in the Atlantic or 
