62 
fractured surfaces of specimens as in microscopic sections ; 
and the margins are apparently plain. 
The tabulae on the other hand are perfectly complete, thin, 
delicate, and about three in the space of one millimeter to 
three in that of two millimeters, but irregularly placed as a 
rule. The original form of the corallites was undoubtedly 
polygonal, but from the deposition of sclerenchyma they have 
become more or less cylindrical and oval, or irregular in section. 
I have not seen any good examples of the surface, but so far 
as observed the mouths appear to be simply at right angles to 
longer axes of the corallites, to be without opercula, and not 
to have either lip raised above the other. 
A very marked difference exists in ramose portions in the 
width of the axial and peripheral portions, the former largely 
predominating, whilst the non-amalgamation of the walls in 
the same region is usually very apparent. Septa seem to be 
absolutely absent, whether as spines or tubercles. I have 
adopted the character of the nural pores as the distinguishing 
feature of F. grandipora , notwithstanding the fact that in some 
species of Favosites the number of pores on each coral lit e face 
is variable. In the present instance, however, the arrangement 
of the pores appears a constant feature throughout a suite of 
tifty specimens, and it may therefore be justifiably used for 
specific distinction in this case. In PI. viii., Fig. 7, is 
represented the horizontal section of the axial region taken 
from a polished specimen, and therein will be noticed the 
broken-up condition of the primordial wall. It is, however, 
nearly always visible at the angles of the cells, to the 
exclusion of the sides, and then has a more or less stellate 
appearance. In some thin sections prepared for the microscope, 
on the other hand, now before me, this wall is tolerably 
continuous and regular. The secondary deposit remains 
very constant in its thickness, and does not appear to attain 
the inordinate growth towards the final period of increase of 
the corallites, so characteristic of the genus Fachypora . 
Class GASTEROPODA. 
Order PEOSOBEANCIIIATA. 
Family EuLiMiDiE. 
Genus Niso, Eisso, 1826. 
(Nist. Nat. Europe, Merid., iv., p. 218.) 
Niso (Vetotuba) brazieri, sp. nov. 
(PI. viii., Figs. 4 & 5 ; PI. ix., Figs. 2 & 3.) 
Sp. Char . — Shell turriculate, polygyrate, subulate, elongately 
conical, and very slowly tapering, straight sided, and no more 
than twelve whorls ; the latter are flat, narrow, with closely 
