84 



ZOOLOGY. 



many simple eyes, each consisting of a cornea and crystal- 

 line cone, connected behind with a long, slender connective 

 rod, uniting the cone with a spindle-shaped body resting 

 on or against an expansion of a fibre of the optic nerve, 

 and is ensheathed by a retina or black pigment mass. 



The lobster's ears are seated in the base of the smaller 

 or first antennae; they may be detected by a clear, oval 

 space on the upper side; on laying this open, a large cap- 

 sule will be discovered; inside of this capsule is a project- 

 ing ridge covered with fine hairs, each of which contains a 



erp 



Fig. 99. — B, third maxillipede; cxp. coxopodite; bp, basipodite; ip, ischiopodite; 

 mp, meropodite; cp, carpopodite: pp, propodite; dp, dactylopodite; c, iuul 

 tiarticulate extremity of exopodite or palpus; flab, epipodite or nabellum. 



minute branch of the auditory nerve. The sac is filled 

 with water, in which are suspended grains of sand which 

 find their way into the capsule. A wave of sound disturbs 

 the grains of sand, the vibrations affect the sensitive hairs, 

 and thus the impression of a sound is telegraphed along 

 the main auditory nerve to the brain. 



The fine hairs fringing the mouth-parts and legs are 

 organs of touch. The seat of the sense of smell in the 

 Crustacea is not yet known, but it must be well developed, 

 as nearly all Crustacea are scavengers, living on decaying 



