MINUTE AQUATIC ANIMALS. 71 



short time they shed their skin, during which process their color fades ; at the 

 same time their vivacity forsakes them and they abstain from food. 



As they recover, their color changes again, and diversified tints adorn their 

 bodies. These creatures are extremely voracious ; for if they are placed in 

 water with other insects, the latter are soon found to be either mutilated or 

 destroyed. 



This Larva, on account of the transparency of the new skin, is in the best condi- 

 tion to be viewed by the microscope soon after it has cast its old skin, as the whole 

 interior organization is then visible. This insect is furnished with two strong jaws, 

 Like a pair of bent pincers, which move horizontally and cross each other when 

 closed. Their color is a bright chestnut, deepening in tint towards the points, which 

 are hard and sharp. The animal seizes its prey with these instruments, and forcibly 

 drawing it towards itself, makes an incision on the body and sucks out the juices. 

 Unless its prey is of great strength the Larva does not kill it before eating, but, 

 seizing on any part within its reach, devours it while its victim is alive. Having 

 finished this portion, it turns the insect round and feeds upon a fresh part, and 

 thus continues its repast until the whole of its prey is consumed, except the 

 skin. 



If the object of attack is a strong, aquatic animal covered with a shell, the 

 Larva either seizes and holds it firmly grasped until it is exhausted by its efforts to 

 escape ; or, springing at it from time to time, cuts oft* its limbs in succession with 

 its powerful nippers ; then, turning the disabled animal upon its back, the ferocious 

 creature pierces the mutilated body, and imbibes its contents. In respect to the 

 other parts of the animal, feelers branch out from the head, each composed of four 

 pieces, connected by joints. On either side of the head is a cluster of eyes, six in 

 each cluster ; in some species they are arranged in a circle at equal distances from 

 one another, while in others three or four are united in a group with the rest a little 

 separated from them. The organs of respiration are seen in their greatest develop- 

 ment at the head, and their course from thence to the tail, through the entire length 

 of the animal, may readily be followed. At the tail the different parts unite and 

 terminate ; they are not simple in their structure, but numerous lateral subdivisions 

 are fchrown out between the extremities of the main organs. 



The entire body of the animal is composed of rings, decreasing in size 

 from the head to the tail, which is forked, and consists of two strong spines 

 with smaller ones branching from their sides. When one of these is destroy- 

 ed, Pritchard observed it to be replaced by another, which seldom, however, 

 attains the size of that which is lost. The Larva is provided with six legs, each 

 consisting of three joints ; bristling with formidable spines, fringed with hairs, 

 and armed at the extremities with strong claws. The front part of the head, 

 immediately below the jaws, is furnished with an arrangement like the teeth of 

 a saw ; but whether this apparatus is really composed of teeth has not yet been 



