518 THE SCALLOP. 
Bennett writes as follows :—“On that part of the body which is lodged in 
the apex of the shell, there is a small, globular, pellucid body, resembling a 
vesicle, and which at night emits a luminous gleam, sufficiently vivid to be 
visible even when it is opposed to the strong light of a lamp. It is the only 
example of a luminous shell-fish I have ever met with ; nor would the 
luminosity of this species be of any avail, did not the shell possess a 
structure so vitreous and transparent. Examples were chiefly captured at 
night or in the evening. 
THE next great group of molluscs is that which is known by the technical 
term of Conchifera. In them each valve corresponds with the right or left side. 
In the first family, of which the common OYSTER is a very familiar 
instance, the two valves are unequal in size, and the animal inhabits the sea. 
The Oyster is too weil known to need description ; but it may be mentioned, 
that practical naturalists have for some years been carefully studying its 
habits, for the purpose of breeding the valuable molluscs artificially, and so 
of securing a constant supply throughout the four months of the year during 
which the creature is out of condition. In this country the system is being 
gradually carried out, but in France it is developed to a very large extent, 
and with great success. 
THE next family are termed wing-shells, or Avicularidze because the 
apices, or “ umbones” as they are called, are flattened and spread on. either 
OYSTER. —(Ostrea edulis.) SCALLOP. —(Pecten jacobeus.) 
side something like the wing of a bird. The interior of the valves is pearly 
and the exterior layer is composed of a kind of mosaic work of five or six 
sided particles. This structure is easily to be seen by means of a 
moderately powerful simple lens, merely by holding upa scallop or other shell 
before the window, so as to allow the light to piss through it. 
THE common SCALLOP is found along our southern coasts, and in the seas 
of Europe. This shell was formerly used as the badye of a Pilgrim to the 
Holy Land. 
‘* ____ His pilgrim’s staff he bore, 
And fix’d the Scallop in his hat before.” 
It is a singular fact, that in the stomach of a common Scallop is found an 
earthy deposit, which, when boiled in nitric acid in order to dissolve the 
animal and other portions, exhibits under a powerful microscope animalcules 
