MYA. 61 



It is impossible to say what were the fives of Aristotle, 

 except that they were not our shells ; nor is it probable 

 that the latter could have come within the scope of his 

 observation, inasmuch as thev are not natives of the 

 Archipelago. The fives w r ere included by him with the 

 xreves (or Pectens) among the bivalves, but they were 

 said to produce spawn-capsules, like the 7rop<f)vpa or 

 Murex trunculus. iEschylus, Atlienseus and other Greek 

 writers also mention fives, but only in such a way as to 

 show that thev were an eatable kind of shell-fish. The 

 Myes of Pliny, that indefatigable naturalist with so 

 little originality, were described by him as " run ac 

 parvi." They may have been Mytilus edulis. The hinge 

 in the present genus resembles that of Thracia in struc- 

 ture, but not in position. In the last-named genus the 

 process in each valve is horizontal, and projects inwards • 

 but in My a it is perpendicular or erect in one valve, 

 and depressed in the other. In each case the office is the 

 same, namely to contain the cartilage. Messrs. Alder 

 and Hancock have carefully investigated the nature of 

 the "branchial currents'''' in My a as well as Pkolas, 

 produced by the action of cilia, and admitted and dis- 

 charged by different apertures ; and the following extract 

 from their excellent paper on the subject, which ap- 

 peared in the 'Annals and Magazine of Natural History' 

 for November 1851, will explain to those who have not 

 studied the economy of the Bivalve Mollusca how this 

 operation is performed, ff We lately had an opportunity 

 of observing Mya arenaria in its native haunts, and 

 watched the play of its siphonal currents under very 

 favourable circumstances. This species, at the mouth 

 of the Tyne, buries itself to a depth of 6 or 8 inches in 

 a stiffish clay, mixed with shingle ; and in shallow r pools 

 left by the tide, the siphonal tubes may be seen just 



