Dr. J. Young on the Malacostraca of Aristotle. 245 



of several other passages : one in the previous chapter is cited 

 by Lewes as at variance with the notion which attributes the 

 absence of limbs in Ostracoderma to their sedentary habits, but 

 seems to admit of an opposite rendering : — " For those animals 

 capable of motion must of necessity have many limbs, because 

 their actions are (many) ; for those partaking of several move- 

 ments have need of several limbs '' (De Part. iv. 7). The mo- 

 dern doctrine, which sees in successive modifications of structure 

 the influence of change of habit resulting from altered conditions 

 of Hfe, finds in Aristotle no anticipation. Of that doctrine the 

 variability of the species is a postulate. But Aristotle sums up 

 his views regarding the persistence of a type in one sentence, 

 which explains the presence of pincers in Astacus : — " they must 

 have pincers, because they belong to a kind which has them^^ 

 (iv. 8). The future consideration of Aristotle's intermediate 

 forms will give occasion to analyze in detail his opinion regard- 

 ing the series of organized forms. Meanwhile it is enough to 

 recall that he recognized no passage, in the modern sense, from 

 one to another. To an advocate of spontaneous generation it 

 was logically inconsistent to admit transition ; the number of 

 known forms was then too small to allow the recognition, even 

 empirical, of any true passage,' even supposing that anatomical 

 research had been more than rudimentary, and had not been 

 limited to such facts as might be obtained by simple inspec- 

 tion. Further, in disproving certain popular errors in terato- 

 logy, he insists upon the essential diff'erences in the period of 

 gestation as negativing the possibility of mixed forms (De Gen. 

 iv. 3). Again, life was to him the active or productive essence 

 of the organism. It had therefore that shadowy impersona- 

 tion which was ascribed to all the energies in the philosophy 

 of his and far later times ; but it was not an abstraction distinct 

 from the organism. Not only was it as a whole 'Hhe energy 

 and faculty '^ of the body as a whole, but its difi^erent Bwd/neL^i 

 find in each part a corresponding hvvafjn^. Since therefore the 

 primary BvvafjLC^ is that to which the subordinate Swd/jLet^ have 

 reference, and since form is not so much the result as the con- 

 comitant of this essential property, it necessarily follows that 

 the manifestation of this final cause must be invariable for every 

 organism (De Anima, i. 3; De Part. i. 1). Admitting its per- 

 manence, and assured of its antecedence to the matter whose 

 changes it determines, we can find for the passages above 

 quoted no other interpretation than that which subordinates 

 structure to function. 



The anterior part of the body, that surface on which the mouth 

 is placed, is called the face. The forehead includes the rostrum 

 and supramandibular space. Beneath the eyes are the antennae 



