PINNA 



Plate XVII. 



Species 31. (Mus. Cuming.) 



Pinna madida. Finn, testa oblique trigond, suban^justd, 

 ad latera incurva, versus umbones acute elevatd, tenui- 

 culd, dense concentrid lamellald, lamellis appressis, 

 subobsolelis, radiatim obscure undato-liratd ; livido- 

 einered, radiis fumeo-nigrescentibus inierrup/is. 



The sodden Pinna. Shell obli(iuely triangular, rather 

 narrow, incurved at the sides, sharply raised towards 

 the umboes, rather thin, densely concentrically lamel- 

 lated, lamella; appressed, ratiicr obsolete, radiately 

 obscurely wave-ridged ; livid-ash, with interrupted 

 smoky-black rays. 



Had. Port Essington, New Holland. 



The concentric lamellfe of this species do not appear 



to be analogous to the scales which predominate in this 



genus, but are an unusual development of the layers of 



ST-OWth. 



Species 32. (Mus. Cuming.) 



Pinna subviridis. Finn, testd trigono-Jlabellatd, mar- 

 gine postico incurvo, aniico rotundato, radiatim coa- 

 tatd, costis squamatis, squamis grandibus, reeurvis, 

 subtiibulosis, costarum inierstitiis late concavis, latere 

 aniico conspicue concenfrice corrugato ; olivaceo-viridi, 

 6-ubpellucidd. 



The greenish Pinna. Shell triangularly fan-shaped, 

 posterior margin incurved, anterior rounded, radi- 

 ately ribbed, ribs scaled, scales large, recurved, som-c- 

 vvhat tubular, interstices between the ribs broadly 

 concave, anterior side conspicuously concentrically 

 wrinkled ; olive-green, rather transparent. 



Ilab. SoiUh Carolina. 



A fine semitransparent olive-green species, boldly ribbed 



and scaled, with the anterior side closely concentrically 



wrinkled. 



June, 1858. 



