PINNA 



Species 22. (Fig. a, b, Mus. Cumiug.) 

 Pinna perndla. Finn., testa suhelongaio-JiabelUformi, 

 tenuiculd, ventricosd, sex- ad septem-costatd, costis 

 magnis, squamatis, sgttamis atriplis, tnbulosis, subir- 

 regularibus, suberectis, eostarum iiU'-rstitiis late con- 

 cavis ; tirescente-nibente, squamis oUvaceo-flavo tinctis. 

 The little ham Pinna. Shell somewhat elongately 

 fan-shaped, rather thin, ventricose, six- to seven- 

 ribbed, ribs large, scaled, scales large, tubular, some- 

 what irregular, rather erect, interstices between the 

 ribs broadly concave ; greenish-red, scales tinged 

 with olive-yellow. 



Chemnitz, Conch. Cab. vol. viii. p. 242. pi. 92. f. 785. 

 Hab. ? 



It will be seen that in the young state of this species, 

 represented at Fig. 22 a, the spines are longer and more 

 tubular, and they appear to become broken off or decora- 

 posed with age. This is probably the case with all Pinn<E, 

 and as the shell advances in growth the scales are deve- 

 loped with less precision, ruder in form and more irregular 

 in position. Tjie Pinna pernula is a deep amber-red 

 colour, somewhat resembling that of P. rudis, and the 

 scales have a semitransparent yellowish tinge. 



May, 



