based on the principle of Cephalization. 323 
grade); as that in passing from the t yRe of Megasthenes (Quad- 
rumanes, Carnivores, Herbivores an i 
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B. Fun 
2. Reseojarert 28, transfer of functions backward that belong 
anteriorly in the higher cognate type. 
ses this method, there are the following cases 
. A transfer of members from the cephalic to ihe locomotive 
ietiea: as the transfer of the fore-limbs to the locomotive series 
illipeds or posterior mouth-organs to the locomotive series in 
eating from Insects to Spiders; that of two pairs of maxillipeds 
to the locomotive series in passing from Decapod to Tetradecapod 
Crustaceans. 
6. A transfer of locomotive or prehensile power and function, 
more or less completely, from the anterior locomotive organs to 
the posteri 
c. A transfer of the locomotive function, more or less com- 
petly, from the limbs (these often becoming obsolete) to the 
y, and mainly to the caudal extremity. 
Under 6 and c, the condition may be described as 
(a) Prosthenic, (from the Greek 290, before, and eho. strong,) 
if the anterior locomotive organs have their normal superiority. 
(0) Metasthenic (from pete after, etc.), if a posterior a is the 
more important and the anterior are weak or obsolete 
‘whith the: Peving (the elytra) do not aid in that or bak 
little, are metasthenre. Fleas, which are degra adati ional es 
the longest and stro Among Macrural Crustaceans, the 
strongest mgeetate are, in the he hi er species, the first pair; in others 
F-ocpoen the ers still inferior - Penzeids) the 
Am. Teng: Sci.—Sreconp Sexiss, Vou. XXXVI, No. 108.—Nov., 1863, 
42 
