MACTRA.— Plate XIII. 



Species 63. (Mus. Cuming.) 



Mactra DoNACiroEMis. Mact. testa ovato-trigond, iu- 

 aqualiterali, turgidd, semicordatd; umbonibus acutis, 

 oppositis, distaniibus, transversim tenuissime striatd, sub 

 epiderniide fidvd albd, antice obtusd, postici late pland 

 et angulatd, extremitaie acuminata. 



The Donax-shaped Mactra. Shell ovately triangular, 

 inequilateral, swollen, semicordate ; umboes sharp, 

 opposite, distant, transversely very finely striated, 

 white, beneath a fulvous epidermis, anteriorly obtuse, 

 posteriorly broadly flat and angled, acuminated at 

 the extremity. 



s. Gray, Ann. and Mag. Nat. Hist. 

 Beechey's Voyage, Moll. p. 154. pi. 



Mulinia Donaciformi 

 1837, p. 376. 

 44. f. 13. 



Hab. New Zealand. 



A very characteristic species, resembling particularly 

 the form of the Z)o;Ma;-shaped species of Area. 



Species 63. (Mus. Cuming.) 



Mactra virgo. Mact. testa ovato-trigond, stibaquila- 

 terali, crassd, solidd, depressiusculd, irregulariter 

 transversim crebristriatd, intus extmque candidissimd, 

 nitente, utroque latere aqualiter declivi, antice obtusd, 

 postice acuminata, subjlexuosd; umbonibus minimis, 

 acutis, appro.timatis ; lunula aredque lavigatis ; sinu 

 pallii brevi, lata, ohtuso, ohliquo. 



The virgin Mactra. Shell ovately triangular, nearly 

 equilateral, tliick, solid, rather depressed, irregularly 



transversely closely striated, very white within and 

 without, shining, both sides equally slanting, ante- 

 riorly obtuse, posteriorly acuminated, subflexnous ; 

 umboes very small, sharp, approximated ; lunule and 

 area smooth ; sinus of the mantle short, broad, ob- 

 tuse, oblique. 



Deshayes, Pro. Zool. Soc. 1854. 



Hab. Swan River. 



An ivory-white solid shell, of a depressly triangular 

 form, rather flexuously acuminated on the posterior side. 



Species 64. (Mus. Cuming.) 



Mactra Dysoni. Mact. testa transversim. oblongd, sub- 

 trigond, compressd, subaquilateraU, postice leviter acu- 

 minata, sub epiderniide Jlavescente tenui calcareu-albd, 

 irregulariter transversim striatd; umbonibus subacute 

 angulatis; lunuld aredque subangulatis. 



Dyson's Mactra. Shell transversely oblong, subtrian- 

 gular, compressed, nearly equilateral, posteriorly 

 slightly acuminated, chalk-white, beneath a thin yel- 

 lowish epidermis, irregularly transversely striated ; 

 umboes rather sharply angled ; lunule nnd area 

 slightly angled. 



Deshayes, Pro. Zool. Soc. 1854. 



Hob. China. 



Of a peculiarly delicate opake chalk-white, beneath a 

 very slight yellowish epidermis, compressed and angled 

 towards the umboes. 



