AVICULA. 



Plate 

 Species 47. (Pig. «, 4, Mus. Cuming.) , 



AvicuLA Tarentina. Jvic. (es(d oMi//ue ovatd, postice 

 acute alatd, Icevigatd vel obsolete costald, coticentrici I 

 Jibroso-lamiiiatd, laminis sp'mk muricatis obsitd ; sor- I 

 (liJe olivaced, purpitrascente-fusco radiatd. 



'i'HE Tabentum Avicula. Shell obliquely ovate, pos- 

 teriorly sharply winged, smooth or obsoletely ribbed, 

 concentrically fibrously laminated, laminae beset with 

 prickly spines ; dii-ty olive, rayed with purplish-brown. 



Mytilus hirundo, pars, Linnaeus, Syst. Nat. 12th edit. p. 

 1159. 



Avicula hirundo, Tiirton. 

 Avicula Tarentina, Lamarck. 

 Amcula falcata, Lamarck. 

 Avicula aculeata, Sowerby. 

 Avicula Anglica, Brown. 

 Avicida Atlaidica, Brown. 



}lab. Mediterranean. 

 This well-known species, which is not uncommon in 



the Mediterranean, occurs with rarity on our own coast. 



The prickly spines are projected from its fibrous epidermis. 



Species 48. (Mus. Cuming.) 

 .'VvicuLA IRIDESCENS. Avic. lestd oblique trigond, con- 

 veximcnld, postice late simiafd, striis mimlis uudu- 



XIIL 



latis undique exsculptd, versus marginem fimbriatis ; 

 aurantio-rufd, suiiridesce/ile. 



The iridescent Avicula. Shell obliquely triangular, 

 i-ather convex, posteriorly broadly sinuated, sculp- 

 tured throughout with fine waved stria;, festooned 

 towards the margin; orange-red, somewhat irides- 

 cent. 



Hab. Moluccas. 



Of very oblique growth, but not materially winged, of 



a bright orange-red colour, having a bronze or iridescent 



hue. 



Species 49. (Mus. Cuming.) 



AvicDLA castanea. Avic. testa subanguste trartwersd, 

 perobliqud, coHvexiusculd, postice subprodtcctd, minute 

 undato-striatd, striis versus margitiem fimbriatis ; in- 

 tense purpureo-castaned. 



The chestnut Avicula. Shell somewhat narrowly 

 transverse, very oblique, rather convex, posteriorly 

 somewhat produced, finely wave-striated, striEe fes- 

 tooned towards the margin ; dark pui-ple-chestnut. 



Hab. Island of Mindoro, Phibppines ; Cuming. 



The form of this species is narrower transversely and 



more winged than the preceding species, and in colour 



it is of a very dark purple-chestnut. The sculptm-e is 



similar. 



March, 1857. 



