MYTILIDA, 167 
longitudinal undulating granulose ribs; bluish or reddish-purple ; in- 
terior violet ; a single small tooth in the right valve. 
Eleicht-er-o5); length, 3. 
Common from Cook Strait southward. Chatham Islands. South 
America. Auckland Islands. Campbell Island. Kerguelen’s Land. 
M. polyodontes, Quoy, 2.¢., Ui., p. 462, pl. 78, f. 15-16. Similar 
to the last, but with eight or ten nearly equal teeth at the extremity of 
the hinge. Founded, I think, upon an erroneous observation. 
M. latus, Chemnitz (not of Lamark ;) Reeve, Conch. Ic., f. 12 and 
J. 243; M. smaragdinus, CMM. ; M. canaliculatus, Martyn? Oblong, 
beak obtuse, swollen, smooth, margin even ; covered with an olivaceous 
brown epidermis, under which it is green varied with chestnut-brown ; 
margin green ; inside purplish-white, iridescent; hinge with one or two 
small teeth. 
Height, 3 ; length, 8°75. 
A very variable shell ; sometimes small specimens are bright-green, 
and sometimes pale yellow. 
Common throughout New Zealand. ‘Tasmania. 
The young can hardly be distinguished from JZ smaragdinus of 
China. 
M. edulis, Z. Reeve, Conch. Ic., f 33; M. dunkert, Reeve, lc, f 
17? Oblong, oval, dilated and compressed behind ; umbones slightly 
uncinate ; covered with a dark olive-brown epidermis, below which it is 
blue ; inside bluish-white, muscular impressions and a band round the 
margin blackish-blue ; three or four small teeth in the left valve and 
one in the right. : 
Height, 1°6; length, .3. 
Common in the South, not so common in the North. Great 
Barrier Island. Auckland Islands. Campbell Island. 
This. may be the JZ. canaliculus, of Hanley, which is also found in 
Kerguelen’s Land ; and perhaps JZ. wzgwlatus, Chemnitz. 
M. ater, Frauenfeld, Reise der Novara, Moll., pl. 2, ff 29-30. 
Small, oblong, inflated, black, obsoletely concentrically striated, covered 
with a shining coriaceous epidermis ; narrow and obtuse in front, 
rounded behind; umbones tumid; dorsal margin declining in front, 
straight behind, near the base sub-parallel ; ventral margin sub-sinuated, 
pearly, sub-fuscous or livid, slightly iridescent (Frauenteld.) 
Height; “5's lenpth, 2: 
Common. Auckland to Dunedin. 
Sub-Family— Crenelline. 
Hinder part of the mantle produced, forming false siphons. 
Genus, CRENELLA—Brown. 
Mantle closed anteriorly ; anal tube perfect and produced. Shell 
short and tumid; centre smooth and both ends ornamented with radia- 
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