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THE JOINTED ANIMALS 



Order AMPHIPODA 



The Amphipods are allied to the Isopods, but the majority are recognizable by 

 having the body narrow and flattened from side to side, instead of broad and 

 flattened below. Moreover, the gills are attached to the thoracic feet, and the 



latter, instead of being broad, leaf -like, 

 and overlapping, are foot-like, elongate, 

 and used for leaping or swimming. 



In the suborder Gammaridea the 

 eyes are mostly of small size, and seldom 

 prominent. The head does not coalesce 

 | with the first segment of the thorax, and 

 1 the maxillipedes have a distinct palp; 

 the abdomen being well developed, and 

 \ bearing appendages. The form of the 

 body is shown in the illustration of the 

 | fresh-water shrimp {Gammarus pulex), 

 and the sand hopper {Talitrus locusta). 

 The latter lives near the edge of the sea, 

 beneath seaweed, or other substances, 

 which prevent the evaporation of the 

 moisture from the sand. Sand hoppers 

 usually progress on land by leaps; and 

 although some nearly allied forms are 

 found far from the sea, the majority of 



the Gammaridea are marine, swimming by means of the constant play of their 

 abdominal appendages, and, when thrown on the land, wriggling helplessly along 

 on their sides. The fresh-water shrimp is common in 

 the streams and ditches of Europe. During the cold 

 months of the year they bury themselves in the mud, 

 but emerge from their winter quarters on the first 

 warm days of spring. Among deep-water forms, per- 

 haps the most noteworthy are Acanthechinus tricarin- 

 atus, and Andania gigantea. The former has de- 

 veloped a spiny process at almost every possible 

 point, each of the principal segments bearing three 

 large and pointed spines, which have their edges 

 armed like the blades of a saw. Very different is 

 Andania, which is one of the largest of amphipods, 

 reaching a length of two inches. Many members of 

 the group construct tubular dwelling places, in which 

 they take shelter, and lay their eggs. For instance, 



the British Amphitha rubricata, which is a brilliant SKELETON SHRIMP. 



crimson color, builds a nest of particles of seaweed (Somewhat enlarged.) 



GIGANTIC ANDANIA, Andania gigantea. 

 (Natural size.) 



