SECT. VII. 



CRUSTACEA. 



207 



scarlet tufted antennae longer than itself spread out at 

 right angles from its head. This creature shone with a 

 bright phosphorescent light, visible even when a candle 

 was burning. These and many more were taken in tropi- 

 cal seas. They were remarkable for the length of their 

 antennae ; and it was observed that no eyes were per- 

 ceptible in such Crustacea as had these exaggerated 

 antennae ; these organs of intelligence and warning were 

 probably sufficient for their wants. When animals live 

 without eyes on the surface of a tropical sea, it is quite 

 conceivable that similar instruments of touch may suffice 

 for those who live in the dark abyss below. 



The Ostrapods, which form the second order of the 

 bristly-footed Crustacea, are defended by a bivalve 

 carapace ; they have swimming limbs and a confluent 

 eye ; that is, a number of simple eyes placed under a 

 glassy cornea. 



The genus Cypris belongs to this group. Several 

 species may be seen swimming in our streams and 

 fresh-water pools. The 

 body of the common 

 Cypris (fig. 151) is 

 enclosed between two 

 flat oval shells, united 

 by a hinge on the back. 

 The little animal can 

 open and shut the 

 valves by means of two 

 slender muscles, ex- 

 tending from its back 

 to the shells, which 

 are much curved above and rather flat below. There 

 are two pairs of antennae beneath the eye, they are 

 perfectly transparent, many-jointed, and end in tufts of 

 filaments. One pair projects forward and then bends 

 gracefully backwards ; the other pair are bent down- 



rig. 151. Cypris. 



