M Y T I L U S. 



Plate VII. 



Species 25. (JIus. Cuming.) 



Mytilus crassus. Myt. testa elongato-flabelUfornii, pos- 

 tice arcnatd, late gibbom, nndique radiatim undato- 

 striatd, striis cremdath ; intense rvfo-purpured. 



Thk thick Mytilus. Shell elongately fan-shaped, pos- 

 teriorly arched, broadly gibbous, radiately wave-stri- 

 ated throughout, striio crenulated ; deep reddish- 

 purple. 



Septifer crassus. Danker. 



Uab. ? 



A dark reddish-purple shell, wave-striated throughout, 

 with a characteristic septum across tiie interior of the um- 

 bonal extremity of each valve, and which is regarded by 

 authors as the type of a distinct genus, Septifer. 



Species 26. (Mus. Cuming.) 



Mytilus Menkeanus. Mi/t. testa subtrigono-elonyaia, 

 solitld, valde gihbosS, radiatim valide corrugato-cos- 

 taid, costis antice divergentibiis, ared posticd lata, de- 

 pressd, creberrime crenulato-Uratd ; nitente luteo-cas- 

 taned, intiis intense purpurea. 



Menke's Mytilus. Shell somewhat triangularly elon- 

 gated, solid, very gibbous, radiately strongly wrinkle- 

 ribbed, ribs diverging anteriorly, posterior area broad, 

 depressed, very closely crenulately ridged ; shining 

 yellowish-chestnut, deep purple in the interior. 



Philippi, Dunker, MS. in Mtis. Cuming. 



JM. New Holland. 



The sculpture is curiously developed, on the same plan, 

 but in three different degrees. The posterior, anterior, 

 and middle areas present a striking contrast. 



as representing Mytilus pictus. Born, 

 M. Afer, Gmelin, described at Plate II. 



Species 28. (Mus. Cuming.) 



Mytilus smaragdinus. Myt. testa elongato-oblougd, 

 convexd, margine antico declivi-angulatd, lievigatd aut 

 decussatim striata, latere postico swbrecio, medio leviter 

 arcuato; nigro-olivaced, versus margitiem vivide sma- 

 ragdind. 



The bkight-green Mytilus. Shell elongately oblong, 

 convex, slo])ingly angled at the anterior margin, 

 smooth or decussately striated, posterior side nearly 

 straight, slightly arched in the middle; very dark 

 olive, bright-green towards the margin. 



Chemnitz, Conch. Cab. vol. viii. pi. 83. f 745. 



Mytilus opalinus, Lamarck. 



Hah. Borneo. 

 This well-known species, in an advanced stage of growth, 



with the epidermis more or less worn oft' or eroded, shows 



a pearly structure, and is in this state the M. opalinus of 



Lamarck. 



Fig. 27. (Mus. Cuming.) 

 This shell, here figured and which Mr. Cuming possesses 



Species 29. (Mus. Cuming.) 



Mytilus Grunerianus. Myt. tesldelongato-Jlabelli/ormi, 

 postice late gibbosd, subrectd, antice ad margineni de- 

 clivi-arcnatd, lavigatd, nitente, concentrice corrugato- 

 striatd ; lutescente-spadiced, ad margineni purpureo- 

 nigrd, intus plumbeo-carnled. 



Gruner's Mytilus. Shell elongately fan-shaped, pos- 

 teriorly broadly gibbous, nearly straight, anteriorly 

 slopingly arched at the margin, smooth, shining, con- 

 centrically wrinkle-striated; yellowish-fawn, purple- 

 black at the margin, lead-blue in the interior. 



DuNKEK, }jiSCm Mus. Cuming. '< ij 



Hab. Iceland. 



A fine new species, of a peculiar yellowish-fawn-colour, 



richly coloured towards the margin with purple-black, 



while the interior is of a dull leaden-blue. 



August, 1857- 



