BARNACLES. 



193 



by their divergence. They resolve themselves into six 

 pairs of arms ; for each one is branched from the basal 

 joint, dividing into two equal and consimilar portions. 

 Those nearest the mouth are the shortest ; and each pair 

 increases regularly in length to the most distant, which 

 are the central pair when the hand is extended. Each 

 division of each of this longest and most extensile pair 

 comprises, in the specimen before us, thirty-two joints, 

 while the shortest consists of about ten, the intermediate 

 ones being in proportion ; so that the whole apparatus 

 includes nearly live hundred distinct articulations; a 

 wonderful provision for flexibility, seeing that every 

 joint is worked by its own proper system of muscles. 



Moreover, every separate joint is furnished with its 

 own system of spinous hairs, which are doubtless delicate 

 organs of touch, since it has been established that the 

 hairs with which the shelly coats of Crustacea are studded, 

 pass through the substance of the latter, and communicate 

 with a pulpy mass, richly sup- 

 plied with nerves, which lines 

 the shell.* These hair3 project V $P& 

 at a more or less wide angle 

 from the axis of the linger-like 

 filament, and are graduated in 

 length; and, what is very striking, 

 as illustrating the exquisite work- 

 manship of the Divine hand, the 

 hairs themselves are compound 

 structures ; for under a high 

 power they seem to be composed 

 of numerous joints, — a deceptive 

 appearance, probably, what look /$ 

 like joints being rather successive . . / / v 'fl\ 

 shoulders, or projections and con- 

 strictions of the outline, — while 



HIND OF BABNACLE. 



* "Pioc. Royal Society," ix. 215. 

 O 



