MOLLUSCA : TnEIR EYES. 59 



)'et even then the two rows of gem-like eyes are dis- 

 tinctly visible, peeping out from the almost closed shell, 

 the two appearing like one undulating row from the 

 closeness of their proximity. 



If you are familiar with the pin-cushions which 

 children often make with a narrow ribbon round the 

 edges of these very Scallop-shells, you can hardly fail 

 to be struck with the resemblance borne by the living 

 animal to its homely but useful substitute ; and the 

 beautiful eyes themselves might be readily mistaken 

 for the two rows of diamond-headed pins, carefully and 

 regularly stuck along the two edges of the pin-cushion 

 ribbon, — the ribbon itself representing the satiny and 

 painted mantle. A friend of mine, to whom I was 

 once showing this object, compared it, not inaptly, to a 

 lady's ring set with diamonds. 



You will not fail to remark, how the position of 

 these beauteous organs is suited for their most extensive 

 usefulness cunsistent with their safety. In the ordinary 

 condition of the animal's expansion, and especially when 

 it is about to make its sudden and vigorous leaps, the 

 gemmeous points are so situated as just to project be- 

 yond the margin of the shell. So that when we view 

 the creature perpendicularly as it lies, our eyes looking 

 down on the convexity of the upper valve, the minute 

 eyes are seen, all round its circumference, just, and but 

 just, peeping from under its edge. It is clear that this 

 arrangement secures to them the widest ranoe of vision 

 with the least possible exposure. As Divine contriv- 

 ance has been often most deservedly recognised in the 

 projection of the bony ridge over the human eye, which 

 we call the brow, we surely cannot fail to recognise, and 

 admire it also in the position of these delicate organs, 



