204 CRUSTACEA. PAKT in. 



enclosing the minute bodies of these animals, is often 

 so transparent that their internal structure, and occa- 

 sionally the process of the assimilation of the food, is 

 distinctly seen by the aid of a microscope. Small as they 

 are, their beauty is often very great ; when transparent 

 they sometimes radiate all the prismatic colours; 

 when opaque, they are frequently of the most brilliant 

 and varied hues, others shine with vivid phosphores- 

 cent light. The segments of their bodies are often very 

 numerous, and similar to one another ; but their appen- 

 dages are very different. They form two distinct natural 

 groups of the bristly-footed and gill-footed Crustacea. 



Copepoda. 



The first order, Copepoda, or oar-footed tribe, have 

 a distinctly articulated body formed of movable rings, 

 bristly swimming limbs ; and the females carry their 

 eggs in huge pouches suspended on each side of the 

 posterior part of their bodies. 



The Sapphirina fulgens is a beautiful example of the 

 two-eyed tribe ; its body is nearly oval, divided into 

 nine distinct joints, and so flat that it is almost folia- 

 cious. The head has two brilliantly coloured eyes, with* 

 large cornea so connected with the shell that they look 

 like spectacles. The two pairs of antennae are silky, 

 and the last pair of foot-jaws that cover the mouth are 

 garnished with silky plumes. It has five pairs of swim- 

 ming feet, and the tail ends in two little plates. 



The Sapphirina is about a line and a half long, of a 

 rich sapphire blue, and floats on the surface of the 

 Mediterranean and tropical oceans. It shines with the 

 most brilliant phosphorescent colours, passing from 

 deep blue to a golden green, or splendid purple. The 

 brilliant colouring is seated in the layer of cells that 

 secrete the firm substance of the body. With a micro- 



