ORDER CRUSTACEA HETEROBRANCHI^. 137 



turn, destroy others that are smaller than themselves, — 

 seizing upon every animal substance they are able to 

 manage that comes within their reach, and, if placed in 

 a vessel of sea-water by themselves, devouring each 

 other. 



The species represented in the engraving has been 

 called the Mi/sis chamceleon, from its colour varying 

 according to the substances on which it feeds, through 

 all the gradations of gray, black, brown, and pink. 



ORDER CRUSTACEA HETEROBRANCHIJE. 



(Crustacea with Organs of Breathing variously 

 placed^ never concealed.) 



The Crustacea which form this order differ much more 

 from each other than those which are arranged in the 

 last order, and consequently we find among them some 

 very singular in their outward formation. Few of the 

 species appear to be used as food by mankind, but they 

 constitute a great portion of the nourishment of fishes 

 and other inhabitants of the water. They are at times 

 used by fishermen as bait. Many of them are very 

 minute, and form most excellent objects for the micro- 

 scope. They have been divided into several sections, 

 according to their outward form ; but as so little is 

 known of their habits, we shall confine ourselves to a 

 description of some of the best known. 



The Spotted Squill, (Squilla maculata.) 

 The Squill seems to form a connecting link between 

 the last and present order. It is the only genus of the 

 heterobranchial Crustacea in which the eyes are placed 



