Chap. VI.] 



ARACHNIDA. 



227 



the oxygen to the blood. Among the Arachnida, 

 remarkable series of chanes so far followed does not 



B 



Fig. 97. A. View of the lower Margin of the right latnelliferous Appen- 

 dages of the eleventh segment of Limulus polyphemus. 



A. Z, Proximal lamella ; lx. one hundred and fiftieth lamella ; ex, external lappet of 

 the bifid distal prolongation of the appendages. 



B. A similar view of the corresponding appendage of Buthus fcoc7ti. 

 Ix, One hundred and thirtieth lamella ; 



c. A. semi-diagramatic view of one of the respiratory Appendages of a 



Scorpion, to show 



I, The bases of the larnellas exposed by the removal of the integument of 

 the axis, the remnants of which are seen at m ; oc, the projecting portion of 

 axis ; I, proximal lamella. (After E. Ray Lankester.) 



end with the scorpion ; some, like Mygale, have but 

 two pairs of lung-books, and other spiders have but 



