76 LAMELLIBHANCHTATA. 



unequal teeth* and two strong lateral teeth, right valve with a small 

 central tooth, and two bifid lateral teeth ; two ligaments. 

 Australia. Philippines. 



89. P. stowei, sp. nov. Transversely oval, thin, white, pellucid, 

 with rather strong ribs divaricating from the centre and crossed towards 

 the margin by a few distant concentric grooves ; interstices slightly 

 rugose ; margin crenulated at each end. Height, - 3 ; length, - 5. 



Islet Reef, Cook Strait ; two left valves only. 



FAMILY SOLEMYAD^;. 



Elongated, equivalve, very inequilateral, gaping, .invested in a thick 

 epidermis. 



SOLEMYA. 



Cylindrical, ligament concealed, pallial line obscure ; umbones pos- 

 terior ; one compressed very oblique cardinal tooth in each valve ; 

 epidermis dark and horny, extending beyond the margin. 



Atlantic. Mediterranean. Australia. 



90. S. australis, Lnmarlc, I.e., vi., p. 124. Dark brown, rayed 

 with paler, interior greyish. Height, '7 ; length, 1'9. 



Common. Stewart's Island. Australia. 



FAMILY CEASSATELLID^. 



Thick, triangular or cordiform, oblong, generally covered with a 

 brown epidermis-; often ornamented with concentric striae; hinge 

 thick, large, and solid. 



GOULDIA. 



Equivalve, trigonal or sub-trigonal, with concentric stride or lamellae ; 

 lunule distinct ; two cardinal teeth in one valve and one in the other ; 

 two anterior lateral teeth in each valve ; pallial line simple. 



91. G. Isabella, sp. nov. Oblong, obtusely trigonal, compressed, 

 equilateral, smooth, with concentric grooves, which get irregular at the 

 posterior end, lunule lanceolate ; ligament small, sub-marginal ; pallial 

 line very slightly siuuated at the posterior end. Pinkish fawn colour, 

 paler and yellower on the umbones, and often marked with brown 

 longitudinal bands, which are horizontal in the centre but slope 

 outward and downward at each end, crossing the ribs ; interior yellow, 

 pink round the margin. Height, '55 ; length, '75. 



MYTILICARDIA. 



Elongated, very inequilateral, with projecting squamose ribs ; an- 

 terior cardinal tooth triangular and diverging, posterior cardinal double 

 in the left valve, no anterior laterals. 



92. M. eXCavata, Deslmyes, Proc. Zool. Soc., 1852, p. 100. 

 Elongate, transverse, irregular in shape, thick, broadly radiately 

 ribbed, ribs scaly. Yellowish white, covered with a brown epidermis ; 

 inside white, getting brown at the posterior end. Height, '75 ; length, 

 1-5. 



Common. Stewart's Island. Chatham Islands. Australia. 



