BIVALVIA. 45 
has its rays or costae upon the inner surface: the exterior seems to have been glossy, and 
the left valve was probably ornamented with colour in zigzag, somewhat like P. similis ; the 
shell is extremely thin, and the internal coste can be distinctly seen on the outside. The 
auricles are large, as is usually the case in minute species of this genus, and the one on 
the pedal side is the larger of the two; this in the right valve is rounded at the angles, and 
ornamented with about half a dozen elevated and imbricated rays, and sinuated near its 
junction with the shell. In the left valve, the auricle on the pedal side is also larger, but 
it is neither rounded at its upper angles, nor sinuated beneath. It is most probably 
identical with the Paris Basin shell, and is not very distantly related to another small 
fossil species, P. sguama, Scac. (P. pygmeus, Miiust.), but this is said to be furnished with 
as many as twenty rays on the inside of the valves. The figure with this name in ‘ Goldf. 
Pet. Germ.,’ pl. 99, fig. 6 a, 6, appears a larger shell ; but it has the same number of internal 
ribs, and corresponds in other respects. Nilsson, ‘ Petrificana Suecana,’ p. 24, t. ix, fig. 18 
AB, describes a species, P. zxversus, which is intermediate in size between sqvamula, 
Goldf., and pygmeus, Miinst. 
Pecten squamula (Geinitz ‘Charak. der Schicht und Petr. des Siich. Bohm, Kreid,’ p. 88, 
taf. xxi, fig. 8) is altogether a different species. 
10. Pecren 30-rapiatus, J. Sowerby. Tab. IX, fig. 4, a—A, and Tab. VIII, fig. 8. 
Precten 30-rapiatus. J. Sow. in Dixon’s Geol. of Suss., p. 172, t. 3, figs. 30, 31, 1850. 
— 40-RADIATUS. Td. - - - p. 173, fig. 33. 
—  PLEBEIUS. Id. - - - p. 172, figs. 28, 32. 
— MULTISTRIATUS? Morris. Cat. Brit. Foss., p. 178, 1854. 
Spec. Char. P. testd variabilis, equivalvi, orbiculari, radiatim costatd, costis numerosis, 
rotundis vel angulato-sulcatis ; interstitiis interdum squamulis, minimis, asperatis ; quan- 
doque radiatis ; auriculis inequalibus. 
Shell variable, equivalve, orbicular, with numerous ribs, rounded or subangulated ; 
interspaces sometimes with small, rough scales or lines of growth, sometimes with an inter- 
mediate ray ; auricles unequal. 
Diameter, 13ths inch. 
Localities. Bracklesham, Bramshaw (dwards). 
The deposit at Bracklesham Bay has yielded an abundance of specimens belonging to 
the genus Pecten, and these present an unusual amount of variation, rendering a specific 
determination a task of extreme difficulty. Mr. Edwards had previously examined his 
specimens ; the accompanying notes were in his cabinet, and I have his permission to 
transcribe them : 
