SAND-HOPPERS. 



ture. The Amphipods have their limbs arranged in two groups 

 opposed to each other. Their body is generally compressed and 

 curved towards the breast ; they swim and leap with facility, but 

 always lying on one side. Some of them inhabit fresh water, but 

 by far the greater number are marine. 



The importance of these Crustaceans in the economy of Nature 

 is very great making up for the smallness of their size by the 

 immense numbers in which they exist and the ubiquity of their 

 presence. They are ready at the first moment to seize upon the 

 dead matter that constitutes their ordinary food, and thus to act 

 their part as scavengers of the ocean without the least delay, 

 whilst in their turn they furnish an abundance of excellent nou- 

 rishment to fish and other aquatic animals. To this Order belong 



The Sand-hoppers (Gammarus}* These animals may be seen in abun- 

 dance by the sea-side in summer-time, where 

 they carry on a continual warfare against the 

 Annelidans of all sorts found on the shore. 

 Nothing is more curious than to see them, 

 when the tide is coming in, congregated in 

 myriads, beating the sand in all directions 

 in search of their victims. No sooner do 

 they meet with one of their favourite worms, 

 than they attack it, and although it may be 

 ten times their own size, soon kill and de- 

 vour it. They never leave off this work of 

 butchery till they have fairly gone over all 

 the mud upon the shore. They are equally 

 ready to attack the Mollusca, fishes, or even 

 human bodies cast up upon the beach. In 

 their turn, they supply an abundant stock 

 of food to multitudes of shore-birds and fishes. 



Dr. Sutherland relates that in Davis Straits he has seen an entire seal re- 

 duced to a perfect skeleton in less than two days by Gammanis arcticus. 



It is a species of Sand-hopper ( Talitrus}, that is alluded to by Archdeacon Paley, as 

 exemplifying the abundance of happiness bestowed on the lower animals. "Walking 

 by the sea-side in a calm evening upon a sandy shore, with an ebbing tide, I have fre- 

 quently remarked the appearance of a dark cloud, or rather very tliick mist, hanging 

 over the edge of the water, to the height, perhaps, of half a yard, and of the breadth 

 of two or three yards, stretching along the coast as far as the eye could reach, and 

 always retiring with the water. When this cloud came to be examined, it proved to 

 be nothing else than so much space filled with young shrimps, in the act of bounding 

 into the air from the shallow margin of the water or from the wet sand. If any motion 

 of a mute animal could express delight, it was this ; if they could have made signs of 

 their happiness, they could not have done it more intelligibly." 



In order to leap, they bend the appendages to their tail under their body, and then 

 forcibly straighten them as though they were let go by a spring, exactly like the Podurse 

 or spring-tails among insects. 



FIG. 167. TALITKUS SAND-HOPPER. 



* KdftfMfOf, kammaros, a kind of crab or shrimp. 



