52 ITS CIRCUMSPECTION. 



point, while the lips are held firmly together at all 

 other points. The resemblance, indeed, of the mantle 

 to the human lips performing such an action, (a 

 resemblance perhaps more close than flattering) struck 

 me as ludicrously faithful. Nor was the appearance less 

 suggestive of a pair of bellows without a nose, of 

 which the valves were the covers, and the mantle the 

 leathers, discharging their contents from any part of 

 their sides. 



That the Pecten widely opens and forcibly closes 

 its valves, if left uncovered hi/ the water, is doubtless 

 correct ; I have seen my specimen perfoiTQ such an 

 action, and perhaps it might by such means jerk itself 

 from place to place with considerable agility. But I 

 do not think so rude a mode of progression could 

 enable it to select the direction of its leaps, which 

 under water appears to me to be determined with 

 accurate precision. 



I observ^ed also a fact which appeared confiimatory 

 of the supposition that the brilliant points among the 

 tentacles are organs of vision ; viz., that in the ordi- 

 nary state of expansion, and when about to make these 

 quick movements, the gem-like points are so situated 

 as just to project beyond the margin of the shell. 

 So that when the latter is viewed perpendicularly, the 

 eye of the beholder looking down upon its convexity, 

 the minute points are seen, all round its circumference, 

 just, and hut just, peeping from under its edge. It is 

 clear that if they are eyes, this secures to them the 

 widest range of vision with the least possible exposure. 



The death of my little Pecten gave me the opportu- 

 nity of submitting some of the gemmeous specks to 



