PECTENS. 385 



the Thames oyster farms. English buyers pick the grown oysters for 

 Manchester and other large provincial markets,, and the Corporation of 

 Edinburgh, the Duke of Buccleuch, and other proprietors of the fore- 

 shore, have just interfered in time to prevent the total destruction of 

 the trade, when the wild song of the Cockenzie dredgerman might 

 have been left to charm some future antiquary, as it is now said to 

 charm the oyster into the dredge with its refrain : 



" The herring it loves the merry moonlight, 



The mackerel it loves the wind ; 

 But the oyster it loves the dredger's song, 

 For it comes of a gentle kind." 



The Scallop-shell (Pecten) is round, nearly equal-sided, resting on 

 the right valve, which is more convex, and marked with radiating ribs. 

 Linnasus made the mistake of confounding with the Ostrea a great 

 number of shells, which, by their channeled edges and surfaces, 

 strongly reminded one of the arrangements of the teeth of a comb, 

 whence their name of Pecten. They were well known to naturalists 

 long before the time of Linnaeus, under the name of Pilgrims' shells, 

 a name which came into use from the practice which prevailed among 

 pilgrims in the middle ages we know not why of ornamenting 

 habits and bats with the valves of some of the species. 



The shell of the Pecten is in general nearly circular, more or less 

 elongated, and terminated towards the summit in a straight line, 

 forming a sort of triangular appendage called the ear, to which the 

 hinges are attached. The valves are very regular, but with no 

 resemblance to each other. In some species, the shell of which is 

 closely shut, the lower valve is more or less convex than the upper 

 one. In others, both valves are convex. The hinge is without teeth, 

 and the ligament, which is intended to close the shell, is inserted into 

 a triangular depression or dimple. The retractile muscle is unequal, 

 and nearly central. The valves are not nacred inside, and are formed 

 on their exterior surface of numerous fluted channels, which spring 

 from a lobe more or less pointed at the summit, diverging towards the 

 circumference. The edges are sometimes smooth, as in the Watered 

 Pecten (P. pseudamussium, Fig. 175), but more frequently they are 

 formed in strips or scales, as in the Smooth-shelled Pecten (P. glaber, 

 Fig. 176). Upon the whole, however, the Pectens are very variable, 

 but always elegant in form ; the colours are frequently lively and 



2 c 



