32 Greville_, on New Species of Campy lodiscus. 
laterally some distance apart_, as in C. cribrosus, tiiey are so 
closely united in C. diplostictus as to cause the lines to look 
like double filaments divided by transverse septa. The long 
lines_, besides^ alternate regularly at the margin with one, or 
occasionally two short ones_, reminding the observer of the 
lamellae of an Agaric. The shorter lines vary in length from 
a fourth to nearly a third of that of the long ones, which has 
the effect of causing the latter to seem very remote from each 
other at their inner extremity. The central blank space is 
more or less rounded or oval, and in size is usually somewhat 
less than a third of the entire diameter of the disc. 
C. Kittonianus , n. sp., Grev. — Valve circular ; canaliculi 
3 in -001", more than half the radius, fringed with minute 
transverse strise for two thirds of their length. Diameter 
•0058". Fig. 7. 
On Tridacna, West Indies; E. Kitton, Esq. On Spondyli ; 
George Norman, Esq. 
This is the most remarkable species which has come under 
my observation. The canaliculi are exceedingly sharply 
defined, and are singularly conspicuous for about two thirds 
of their length, by being furnished with a sort of ridge or 
crest of minute striae. In a vertical aspect (as in the middle 
canaliculi of the valve) these minute striae entirely cross the 
part, and have the effect of increasing its diameter; but 
when viewed in profile, the striae are seen to constitute a 
raised crest, very much resembling a long, narrow, one-sided 
brush, the naked portion of the canaliculus representing the 
handle. The valve is considerably curved and concave ; and 
in the central space there is a broad vertical bar, dilated at 
top and bottom, as in C. notatus, only less conspicuous, and 
composed apparently of merely a thicker and more opaque 
substance than the rest of the central area. I apprehend, 
however, that no dependence can be placed on this cha- 
racter ; for in several specimens of Campylo discus stellatus, 
which I have recently had an opportunity of examining, 
through the kindness of Mr. T. G. Rylands and Mr. Kitton, 
no two are alike in the characters aff'orded by the central 
markings. 
Of the noble species before me I observed a single frag- 
ment in one of Mr. G. Norman^s slides obtained from the 
cleanings of Spondyli. 
