MACTRA.— Plate XI. 



mis, anterior side rounded, transversely grooved, 

 grooves fading in the middle, posterior conspicu- 

 ously beaked ; lunule and area rather broad, plicately 

 striated ; umboes swolleu, polished, close. 



Deshayes, Pro. Zool. See. 1854. 



Hab. Australia. 



An interesting half-grooved anteriorly beaked shell, 

 having very much the form of Crassatella. 



Species 49. (Mus. Cuming.) 



Mactra Adansoni. Mact. testa ovato-ohlongd, trans- 

 versa, turgidula, subaquilaterali, alho-flatlcante, ni- 

 tente, pallide violaceo angnste multlradiatd, latere an- 

 tico regulariter striata, medio et latere postico lavi- 

 gatis; lunula aredque ovatis, parviusculis, eleganter 

 striatis ; umbonihus subaugulatis, inolaceis. 



Adanson's Mactra. Shell ovately obloug, transverse, 

 rather swollen, nearly equilateral, whitish-yellow, 

 shining, narrowly many-rayed with pale violet, an- 

 terior side regularly striated, middle and posterior 

 side smooth; lunule and area ovate, rather small, 

 elegantly striated; umboes rather angular, violet- 

 tipped. 



Philippi, Zeitschi-ift fiir Malac. 1848, p. 152. 

 Le Lisor, Adanson. 



Mactra lilacea ? Lamarck. 

 Hob. Senegal. 



Approximating in some measure to M. stnltortim, but 

 more transverse, and more regularly violet-rayed. 



Species 50. (Mus. Cuming.) 



Mactra corallina. Mact. testa trigono-suborbiculari, 

 subaquilaterali, tenui, tumidiusculd, eburned, sonulis 

 nonnullis transversalibus luteis aut rufescentibus no- 

 tatd, latere antico hviter concavo-compresso ; lunula 

 indistinctd, postico declivi, obtuse angulato ; area per- 

 ampld convexd ; umbonibus angulatis, confertis. 



The coral Mactra. Shell triangularly suborbicnlar, 

 nearly equilateral, thin, rather swollen, ivory-white, 

 marked with a few yellowish transverse bands, an- 

 terior side slightly concavely compressed, with the 

 lunule indistinct, posterior side slanting, obtusely 

 angled ; area very large, convex ; umboes angular, 

 close. 



LiNN^us, Syst. Nat. (12th edit.) p. 1125. 

 Mactra lactea, Chemnitz. 



Hab. Venice, Sicily. 



xV triangularly rounded shining white species, concavely 

 compressed on one side and convexly angled on the other. 



