based on the principle of Cephalization. 845 
groups, as suggested by different entomologists. The Lepismee 
show their degradational character in their larval forms and 
in other approximations to the Myriapods, and the Podurellids 
appear to be still inferior in having the abdomen elliptic in some 
he Araneoids are Brachyural Spiders; the Scorpionoids, 
Macrural ; while the Acaroids are degradational. The last show 
h 
Spiders in two, cephalothorax, and abdomen, the Acaroids have 
similarly, are degradational Macrurans, with which or a 
which are 
® See also vol. xxv, [2], pp. 337, 338. 
