CHAMA. 
Puate IV. 
Species 16. (Mus. Cuming.) 
CHAMA REFLEXA. Cham. testd orbiculari, planiusculd, 
valve inferiort margine reflexd, valvd superiore squa- 
mis brevibus fornicatis concentricé seriatim dispositis, 
inferiore lamellis irregularibus imbricatis ornatd ; val- 
varum marginibus internis minutissime crenulatis ; ru- 
bido-purpuredé umbones versus albd, squamis posticis 
tantum valve superioris albis aut pallidé stramineis ; 
intus alba, posticé vivide purpured. 
THE REFLECTED CuaAma. Shell orbicular, rather flat, 
margin of the lower valve reflected, upper valve orna- 
mented with concentric rows of short vaulted scales, 
the lower with irregular imbricated lamellee, internal 
margins of the valves very minutely crenulated ; 
reddish purple, white towards the umbones, posterior 
scales only of the upper valve white or straw-coloured, 
interior white, rich purple posteriorly. 
Hab. Darnley Island, North Australia; Jukes. 
The lower valve of this species is probably reflected on 
the anterior side from its having been attached in some 
confined situation; but I notice the character because it 
is also slightly reflected posteriorly, where there appears 
to have been no pressure to intercept the growth. 
Species 17. (Mus. Cuming.) 
CuaMa NivaLis. Cham. testd ovato-oblongd, valde tumidé 
- et globosa, valvis ambabus subobsolete radiatim corru- 
gato-plicatis, ad margines hic illic rudé squamatis aut 
lamellatis ; alba, purpureo-fusco concentrice tinctd. 
THE sNOW-BALL CuamA. Shell ovately oblong, very 
much swollen and gibbous, both valves rather obso- 
letely radiately plicated in a wrinkled manner, rudely 
scaled or lamellated here and there at the margins; 
white, concentrically stained with purple brown. 
Hab. North Australia ; Jukes. 
Of a peculiar subquadrate oblong form, sculptured with 
almost obsolete stunted plaits or immature scales which 
in the upper valve are to a considerable extent abraded in 
the specimen before me. 
Species 18. (Mus. Cuming.) 
CHAMA CORALLOIDES. 
Cham. testé crassiusculd, circuiter 
trigond, sublobatd, minuté rugoso-liratd, postice minu- 
tissimé rugoso-striatd ; albida, liris striisque purpureis, 
intus purpured, cardine vivide corallo-rubro. 
THE RED-coraL Cuama. Shell rather thick, circuitously 
triangular, somewhat lobed, minutely roughly ridged, 
very minutely roughly striated on the posterior side ; 
whitish, ridges and strie purple, hinge bright coral- 
red. 
Chama echinata (ztate provecta), Broderip, Trans. Zool. 
Soc. pl. 39. f. 6 and 7. 
Hab. Porto Portrero, Central America (found attached to 
rocks at low water); Cuming. 
T cannot trace the affinity which Mr. Broderip assumes 
for this species with C. echinata; it is true there is a strong 
indication of the deep coral-red colouring in the interior of 
that species, and it inhabits the same locality, but not only 
does it differ materially in form, but it is characterized by 
a different system of sculpture. No modifying force would, 
I conceive, bring the purple brown spines of the C. echi- 
nata into the two-fold arrangement of undulating ridges 
and striz which characterize the species under considera- 
tion. The interior is most richly coloured, being of an 
intensely dark purple, whilst the hinge-tooth is of a deep 
coral-red ; for illustration of this, I refer the reader to 
Mr. Broderip’s figures in the Trans. Zool. Soe. 
Species 19. (Mus. Cuming.) 
CHamMa RADIANS. Cham. testé semi-globosd, lateraliter 
affiad, valvis ambabus laminis tenuibus brevissimis nu- 
merosissimis plano-appressis, trigono-concentricis, com- 
positis ; albida, ferrugineo-fusco posticé radiatim tincta. 
THE RADIATING CHama. Shell semi-globose, affixed by 
the side, both valves composed of very numerous, 
thin, very short lamine, triangularly concentric and 
flatly pressed one upon the other; whitish, radiately 
stained on the posterior side with rusty brown. 
Lamarck, Anim. sans vert. (Deshayes’ edit.) vol. vi. p.515. 
Hab. 
To judge from the figures hitherto published of this 
species it appears to become attached in pairs; the speci- 
men before me, as well as those represented in the Encyclo- 
pédie Méthodique, and by Chemnitz, being severally dis- 
tinguished for this mode of attachment. 
? 
December, 1846. 
