HARDWICKE'S SCIENCE-GOSSIP. 



181 



"clam." It is eaten, and apparently enjoyed, in 

 many places, about five thousand bushels being- an- 

 nually brought to the Boston market. The most 

 noticeable features about this bivalve arc tiie foot, 

 which is vponderfully flexible, assuming the duties 

 of a digger, or spade, a sharp v^edge, or a bent 

 hook — and the epidermis, whicli is prolonged into a 

 tube, covering the excurrent and incurrent siphons. 

 Not unfrequently they go by the name of the 

 "gapers" among our fishermen, because the shells, 

 ■when denuded of their epidermis, do not meet at 

 one end. Their habit of life is to be buried upright 

 in the sandy mud, with the siphon just projecting, 

 and taking in fresh food and water at the same 

 time. We have already glanced at their geographi- 

 cal distribution, a fact which always proves the 



Fig:. 117. Sand Mussel 

 {My a arenaria). 



Fig. lis. Truncated Sand Mussel 

 (My a truncata). 



geological antiquity of a species, seeing that it is 

 indicative of the time required for it to spread over 

 such an extensive area. This is true of the Sand 

 Mussel. We find it in great abundance in the Nor- 

 wich Crag, a pliocene deposit older than the Glacier 

 epoch. It is even met with in the perhaps still 

 older Red Cray. At Aldeby, in Suffolk, fossil Sand 

 Mussels are very abundant, and are seen with both 

 valves united, standing upright in the stratum of 

 sand, just as they did when alive, untold centuries 

 ago. 



The Truncated Sand Mussel {Mya truncata) is 

 even an older form, geologically speaking, for fine 

 specimens are met with in the early Pliocene forma- 

 tions, as in the Coralline Crag of Suffolk. It is 

 generally regarded as possessing more of an Arctic 

 character than the foregoing species. In the living 



state it occurs as far south as the Black Sea (where 

 H may have been brought during the Glacial epoch) 

 and in the Bay of Biscay. Northerly it is far more 

 abundant, swarming in the seas off Greenland and 

 Massachusetts, and even off Vancouver's Island. 

 Its occurrence in the latter locality is very signifi- 

 cant, as this area is situated so far off the other 

 places where it is abundant, and the most ardent 

 stickler for " special creation " would never contend 

 for two special creations of the Truncated Sand 

 Mussel in two places. Therefore the species must 

 have been long enough in existence to have been 

 disti'ibuted by natural causes, and these widely- 

 severed localities of distribution afford a good idea 

 of the physical changes which have occurred since 

 the species came into existence. In Arctic seas it 

 is sought after and eaten, not only by man, but by 

 the walrus, Arctic fox, and wild ducks. Professor 

 Otto Torell is of opinion that the walrus rakes it up 

 from the mud by means of its long tusks. Off the 

 North American fishing-grounds Gwyn Jeffreys 

 tells us it is equally esteemed a dainty article 

 by the cod. The Arctic variety of this species is of 

 a very persistent type, and was named by Professor 

 Edward Forbes JJddevalensis. This variety occurs 

 in the fossil state in considerable abundance in the 

 Post-glacial beds of the Pirth of Forth and else, 

 where in Britain. The ordinary form of il/. truncata 

 has even been found on Moel Tryfaen, seventeen 

 hundred feet above the sea-level, thus affording us 

 a good idea of the climature of the sea which ex- 

 isted in North Wales when the land was submerged 

 to the above depth. As a rule, the Truncated Sand 

 Mussel is found living in the open sea, thus far 

 being distinguished from Mya arenaria, which is of 

 more littoral habits. J. E, Taylob. 



SNAKE-FASCINATION. 



rriHAT certain animals are endowed with the 

 -^ faculty of fascinating their prey, so that they 

 become incapable of offering any resistance, is now 

 generally admitted as an established fact ; never- 

 theless there hangs over the subject a sonpgon of 

 mystery which induces most naturalists to avoid it 

 altogether, or to declare their disbelief in a pheno- 

 menon which they have never taken the trouble to 

 investigate. 



The mesmeric power is possessed by serpents iu 

 a very high degree, and is supposed to have its seat 

 principally in the eye. There are those who cut 

 the gordian knot by saying that the excessive lustre 

 of this organ simply bewilders the victim ; but this 

 rough-and-ready method of solving the problem is 

 hardly borne out by what is known of the method 

 of fascination. 



A snake, when about to put forth its terrible 

 power, remains perfectly motionless, with neck in- 



