16 
7. Mactra cornEA, Desh. WM. testa magna, ovato-trigona, tur- 
gida, tenui, inequilaterali, transversim tenue et irregulariter 
striata, squalide corneo-flavida, intus alba pallide violascente, 
zonulis saturatioribus interrupta ; latere antico breviori, late ob- 
tuso, subsemicirculari, latere postico attenuato, superne longe de- 
clivi, recto, inferne obtuse angulato ; margine inferiore regulariter 
convexo; lunula plana, indistincta, tenue striata; area elongato- 
lanceolata, excavata, angulo obtuso circumdata; umbonibus an- 
gustis, acutissimis, prominentibus, oblique incurvatis, violaceo- 
lividis ; cardine lato, tenui; dentibus lateralibus lamellosis, latis, 
postico longiore, cardine proximo; sinu pallii brevissimo, lato, 
obtuso, basi dilatato. 
Hab. Chinese Sea. Coll. Cuming. 
8. Macrra eximsa, Desh. WM. testa ovato-transversa, equilate- 
rali, utroque latere equaliter obtusa, levigata, polita, epidermide 
decidua, flavescente vestita, pallide rufescente, eleganter albo mul- 
tiradiata, radtis inequalibus, inequaliter distantibus; lunula 
magna, ovata, in medio carinata, areaque eleganter plicatis ; um- 
bonibus tumidulis, acutis, oppositis ; valvis tenuibus, intus albis ; 
cardine angusto ; dentibus lateralibus magnis, lamellosis, inequa- 
libus, antico majore; sinu pallii brevissimo, lato, regulariter 
arcuato. 
Hab. Australia (Moreton Bay). Coll. Cuming. 
9. Macrra mera, Desh. MM. testa ovato-trigona, turgidula, 
levigata, nitida, inequilaterali, corneo-flavicante, ad umbones 
rubescente, zonulis transversalibus saturatioribus, distanter inter- 
ruptis, intus corneo-rufescente ; latere antico paulo breviore, ob- 
tuso, superne declivi et convevxiusculo; latere postico attenuato, 
valde declivi, umbones versus convexiusculo ; umbonibus depressis, 
parum obliquis, approximatis, acutis ; lunula areaque ovatis, tumi- 
dulis, regulariter plicatis ; linea ventrali pallii latissima; sinu 
postico brevi, obtuso, ad apicem parum dilatato ; dentibus latera- 
libus magnis, compressis, lamellosis, in valva dextra duplicatis. 
Hab. Chinese Sea. Coll. Cuming. 
10. Macrra opesa, Desh. WM. testa ovato-trigona, inequilaterali, 
crassa, tumida, cordiformi, antice obtusa, postice angulata, levi- 
gata, alba, sub epidermide tenuissima griseo-flavescente, tenue et 
regulariter striata; umbonibus tumidulis, oblique cordatis; area 
lunulaque ovatis, regulariter striato-plicatis, planis ; valvis crassis, 
intus albis ; sinu pallit brevi, lato, semielliptico ; dentibus latera- 
libus compressis, antico breviore, eminentiore. 
Hab. Torres Straits. Coll. Cuming and Deshayes. 
11. Macrra mrererricirormis, Desh. M. testa ovato-trigona, 
inflata, turgida, cordiformi, inequilaterali, levigata, albo-grisea, 
apicibus atro-violacea, epidermide fuscescente, transversim striata, 
vestita, antice obtusa, postice angustiore, angulata ; latere antico 
lato, plano, regulariter sulcato ; area elongato-ovata, angulo ob- 
tuso circumdata, eleganter sulcata; umbonibus tumidis, promi- 
nentibus, oblique cordatis ; valvis crassis, intus lilacinis ; cardine 
