628 THE MANTIS SHEIMP. 



appendages near the tail seem to be merely used for the purpose of cleaning its burrow of 

 wood dust which is not required for food. The creature always swims on its back, and when 

 commencing its work of destruction, clings to the wood with the legs that proceed from 

 the thorax. The Wood-boring Shrimp is one of the jumpers, and, like the sand-hopper, 

 can leap to a considerable height when placed on dry land. 



Another wood-boring shrimp will be figured and described in a succeeding page. 



On the left hand of the illustration are seen two figures of a crustacean called 

 appropriately the SKELETON-SCREW, or MANTIS-SHRIMP. There are several species 

 belonging to this genus, and all possess similar habits. Their bodies are indeed skeleton- 

 like in their bony lankness, but their appetites are by no means small in proportion to their 

 size. Indeed, as is often the case with peculiarly meagre human beings, they are most 

 voracious, preying incessantly on every small creature that comes in their way. They are 

 furnished with terrible instruments of prehension, their first and second pairs of legs being 

 devoted wholly to this purpose. The last joint but one is enormously large, and the last 

 joint is thin, and shuts down like the blade of a clasp-knife into its haft, the groove being 

 represented by a double row of spines between which the blade is received. The blade 

 itself is finely notched along the edge. These claw-like terminations to the legs are used 

 not only for seizing prey, but for grasping the branches and drawing the long attenuated 

 body from one part to another, 



Mr. Gosse, who has paid much attention to these curious beings, remarks that their 

 movements among the marine vegetation are wonderfully like those of the spider monkeys 

 among the branches, their long thin bodies adding to the resemblance. They run about 

 with great agility, and are always to be found in the branches of the Plumatella cristata. 

 The same writer has given a very interesting history of the Mantis-shrimp : 



" Their manners are excessively amusing. The middle part of their long body is destitute 

 of limbs, having instead of legs two pairs of oval clear vesicles, but the hinder extremity is 

 furnished with three pairs of legs armed with spines, and a terminal hooked blade like that 

 already described. With these hindermost legs the animal takes a firm grasp of the twigs 

 of the polypidom, and rears up into the free water its gaunt skeleton of a body, stretching 

 wide its scythe-like arms, with which it keeps up a see-saw motion, swaying its whole 

 body to and fro. Ever and anon the blade is shut forcibly upon the grooved haft, and woe 

 be to the unfortunate infusorium, or mite, or rotifer that comes within that grasp ! The 

 whole action, the posture, figure of the animal, and the structure of the limb, are so 

 closely like those of the tropical genus Mantis among insects, which I have watched thus 

 taking its prey in the Southern United States and the West Indies, that I have no doubt 

 passing animals are caught by the crustacean also in this way, though I have not seen 

 any actually secured. 



The antennae, too, at least the inferior pair, are certainly, I should think, accessory 

 weapons of the animal's predatory warfare. They consist of four or five stout joints, each 

 of which is armed on its inferior edge with two rows of long stiff curved spines, set as 

 regularly as the teeth of a comb, the rows divaricating at a rather wide angle. From the 

 sudden clutching of these organs, I have no doubt that they too are seizing prey ; and very 

 effective implements they must be, for the joints bend down towards each other, and the 

 long rows of spines interlacing must form a secure prison, like a wire cage, out of which 

 the jaws probably take the victim, when the bending in of the antenna has delivered it 

 to the mouth. 



But these well-furnished animals are not satisfied with fishing merely at one station. 

 As I have said above, they climb nimbly and eagerly to and fro, insinuating themselves 

 among the branches, and dragging themselves hither and thither by the twigs. On a 

 straight surface, as when marching (the motion is too free and rapid to call it crawling) 

 along the stem of a zoophyte, the creature proceeds by loops, catching hold with the fore 

 limbs, and then bringing up the hinder ones close, the intermediate segments of the thin 

 body forming an arch, exactly as the caterpillars of geometric moths, such as those for 

 example that we see on gooseberry bushes do. But the action of the crustacean ifi 



