

ZOOLOGY R)K MKDICAL STl'DKXTS 



CHAP. 



iiiiinous wall which allows ready respiratory exchange of gas 

 the Mood within and tin- sea-water without. 



PI INS arc Arachnids which have forsaken the sea and taken 

 nee, and their appendages, while agreeing exactly 



met. 



99 . 



; /.,-. I.it.-r..l eyes; mes, niesnsoma ; met, meta- 

 D. I. ( h.'hci-r.i ; 11, petlipalp; III-VI, walking legs. 



A ill) those ol I.juiulus, show interesting modifications in 



The first appendages (I), as in Limulus, are small 



1 1 -VI) are walking legs. These are more 



der t! '' I.iinlns and, excepting II (pedipalp), 'which is stout 



and chelate, posse- a ^harply clawed foot. The pedipalps are of special 



