342 THE LIMA. 



foot, developed from the centre of that portion of the 

 body which includes the viscera, is furnished with the 

 power of producing a tenacious kind of secretion, which 

 hardens in something like the same manner as the cobweb, 

 after leaving the spinneret of the spider, and thus con- 

 stitutes a temporary kind of byssus ; which is somewhat 

 remarkable, as the Lima is a most locomotive mollusk, 

 and endowed with as much animation and vivacity as a 

 Pecten; and from another reason that most lamelli- 

 branchiate mollusks, which spin a byssus, have the foot in 

 general but very little developed. The Lima usually 

 live quietly at the bottom with the valves widely extended 

 and thrown flat back, like the wings of certain butter- 

 flies, when basking in the sun; but when disturbed, they 

 start up, flap their light valves, and move rapidly through 

 the water, by a continued succession of sudden jerks. 

 The cause of alarm over, they bring themselves to an 

 anchor by means of their provisional byssus, which they 

 seem to fix with much care and attention, previously ex- 

 ploring every part of the surface with their singular leech- 

 like foot. When many hundreds of these curious bivalves 

 are seen at the bottom of clear pools, surrounded by 

 living branches of party-coloured coral, their crimson 

 spotted mantles and delicate spiral appendages that fringe 

 the edges, cause them to exhibit a very rich and beautiful 

 appearance. 



Although M. Quoy has rightly termed the Mitra an 

 " animal apathetique," yet among the Philippines, and in 

 the China Sea, about the low coral islands, I have seen 

 the small longitudinally-ribbed species crawl about pretty 

 briskly over the smooth sand. The Mitra episcopalis, 



