PEC TEN. 



551 



them when required by spinuing a temporary byssus. The 

 young swim freely about in a rapid and zigzag manner by 

 the sudden opening and closing of their valves. The 

 structure of the shell, according to Dr. Carpenter, con- 

 sists of membranous, corrugated lamella?, disposed in two 

 layers, with occasional traces of cellularity on the external 

 surface, which sometimes assume the character of a pris- 

 matic cellular layer. The Pectens, as shown by Lesson, 

 are enabled to leap out of the water by striking their valves 

 rapidly together. The surface of the valves is usually 

 adorned with brilliant and varied colors. Pecten maximus 

 and P. opercularis are regarded by epicures as dainty 

 articles of diet. The shell of P. Jacoha>iis was formerly 

 worn as a badge by pilgrims who had been to the Holy 

 Land. The Pectens are world-wide in their geographical 

 distribution, and are very numerous in species. 



Sjwcies of Pecten. 



altus, Reeve. 

 asperrimus, Lam. 

 asperulatus, Adams and Reeve. 

 aurautiacus, Adams and Reeve. 

 australis, Sow. 

 blandus, Reeve. 

 Bruei, Payr. 

 circularis, Sow. 

 cloacatus, Reeve. 

 concinnus, Reeve. 

 corallinoides, D'Orb. 

 coruscans, Hinds. 

 cretatus, Reeve. 

 cristularis, Adams and Reeve. 

 crotilus, Reeve. 

 cruentatus, Reeve. 



Cumingii, Reeve. 

 cuneolus, Reeve. 

 Darwinii, Reeve. 

 daucus, Reeve. 



denticulatus, Adams and Reeve. 

 Bieffenbachi, Gray. 

 distans, Lam. 

 Dringi, Reeve. 

 effulgens, Reeve. 

 erubescens, Reeve. 

 exasperatus, Soiv. 

 Fabricii, Reeve. 

 florens, Lain. 

 fricatus, Reeve. 

 fucatua, Reeve. 

 fulvicostatus, A damsandReeve. 



