414 SOLEN; MYA; BYSSOMIA. 



the holes are often seen in considerable numbers; and this is 

 also the time when the animal may be most easily procured. 

 The fisherman throws a little salt upon the hole, which induces 

 the animal to ascend, according to some, by leading it to the 

 belief that the tide had returned, and, according to others, by an 

 irritating effect of which it desires to get rid. To seize it when 

 it makes its appearance, some address and quickness are required; 

 for it speedily returns to its burrow; and, if entrapped, its 

 struggles are sufficiently powerful to cause injury by the sharp 

 edges of the shells. If it re-enter its hole, fresh pinches of salt 

 no longer produce the same effect; the animal having either 

 learned by experience that they do not indicate the return of the 

 sea above it, or deeming it better to submit to the irritation than 

 to expose itself to capture. The fisherman then has recourse to 

 a long iron crook, which he sinks pretty deeply ; and, drawing it 

 out obliquely, carries away the sand, and the Solen contained in 

 it. If he should fail in this attempt,he knows that to try again 

 would be useless; since the animal instantly burrows rapidly 

 down to such a distance, as to render pursuit of this kind useless. 

 957. This group is connected with the preceding by the 

 Mya, Lutraria^ and other genera, which are common on our 

 coasts ; and which burrow into sand or mud. In the Mya and 

 its allies, the two respiratory siphons are united into a single 

 tube, which is of fleshy consistence, and which is covered by an 

 epidermis prolonged over it from the shell. One genus, the 

 'Byssomia, is remarkable for possessing a byssus at the base of 

 its small foot. The shells of this Order are usually covered with 

 a thick epidermis, or horny skin. 



ORDER X. INCLUSA. 



958. The last Order is one of the most interesting of the whole 

 group, as regards the habits of the animals composing it, and the 

 curious varieties of structure which they present. The peculiar 

 disposition of the mantle, which has been noticed as characterising 

 the group (936), has an evident relation with the habits 



