290 RAMBLES OF A GEOLOGIST. 



out its armed head, and arrested, as they passed, the minute 

 animals on which it preyed. The animal world is full of 

 such compensatory defences : there is a half-suit of armour 

 given to shield half the body, and a wise instinct to protect 

 the rest. The Pholas crispata cannot shut its valves so as to 

 protect its anterior parts, without raising them from off those 

 parts which lie behind : like the Irishman in the haunted 

 house, who attempted lengthening his blanket by cutting 

 strips from the top and sewing them on to the bottom, it loses 

 at the one end what it gains at the other ; but, hemmed round 

 by the solid walls of the recess which it is its nature to hol- 

 low out for itself in shale or stone, the interior parts, though 

 uncovered by the shell, are not exposed. By closing its valves 

 anteriorly, it shuts the door of its little house, made, like that 

 of the coney-folk of Scripture, in the rock ; and then, of the 

 entire cell in which it dwells so secure, what is not shut door 

 is impregnable wall. The remark of Paley, that the " human 

 animal is the only one which is naked, and the only one which 

 can clothe itself," is by no means quite correct. One half 

 the hermit crab is as naked as the " human animal," and even 

 less fitted for exposure ; for it consists of a thin-skinned, soft, 

 unmuscular bag, filled with delicate viscera ; but not even the 

 human animal is more skilful in clothing himself in the spoils 

 of other animals than the hermit crab in wrapping up its 

 naked bag in the strong shell of some dead fusus or buccinum, 

 which it carries about with it in all its peregrinations, as at 

 once clothes, armour, and house. Nature arms its front, and 

 it is itself wise enough to arm its rear. Now, it seems not 

 improbable that the half-armed Coccosteus, a heavy fish, in- 

 differently furnished with fins, may have burrowed, like the 

 recent Silurus glanis or Pimelodus gulio, in a thick mud, 

 of the existence of which in vast quantity, during the times 

 of the Old Red Sandstone, the dark Caithness flagstones, the 

 fetid breccia of Strathpeffer, and the gray stratified clays of 



