ORDER AMPHIPODA. 105 



manner as lobsters. The typical species is the Squilla 

 (Cancer) mantis Linn., which is very common in the 

 Mediterranean Ocean. It grows to the length of seven 

 inches. 



The Phyllosomida are called glass-crabs, from the slender 

 and transparent form of their bodies, which is very flat and 

 membranous, divided into two shield-like plates, the anterior 

 very large and oval, forming the head, and the second, or 

 thorax, transverse and angulated. The legs are very long 

 and slender, and each is furnished with a small ciliated 

 branch. These delicate creatures are found in the tropical 

 parts of the Atlantic and Indian Ocean, and one has been 

 discovered in the Mediterranean. When alive they are en- 

 tirely colourless, except the eyes, which are of a rich blue. 

 There are several species, described by Leach and Guerin. 



ORDER III. AMPHIPODA. 



This order is distinguished by the body being generally 

 compressed, and curved upon the sides ; the eyes are sessile 

 and immoveable; mandibles furnished with a palpus; and 

 many of them have vesicular bags either between their feet 

 or at their external base, the use of which is unknown. 



The first pair of feet, or that which corresponds to the 

 second foot- jaws, is always annexed to a particular segment, 

 the first after the head. The antennae, which, except in the 

 Phrominse, are four in number, project and gradually taper 

 to a point ; the tail is articulated and styliform. 



In this, and indeed m the other groups of sessile-eyed, 

 hard-shelled Crustacea (except the Lcemodipoda}, the body 

 is furnished with seven pairs of legs, attached in pairs to 

 the seven equal-sized segments succeeding the head ; but 

 the mouth possesses only a single pair of foot-jaws, so that 

 it is quite evident not only that certain organs which, in the 



