CONTEXTS-SUMMARY 



Introdttctory 



BK. CH. 



1. 1 The Causes. The Motive and Material Causes of animals 



are the main theme of G.A. 



The Sexes 



(a) Distinction of sexes not universal. They are {a) found in 

 mast blooded animals, and in Cephalopods and Cnistacea, 

 but not in all Insects ; (b) not found in Testacea. 

 2 (6) Definition of male and female : they are the " principles " 

 of generation, the male pro\iding the motive agent and 

 the female the material. Hence a corresponding differ- 

 ence in the sexual parts, which vary in the various animals, 

 but are always double. 



1 — Sexual Parts in Blooded Animals 



4 (a) Sexual parts in males. The purpose of testes. 

 8 (b) Sexual parts in females : 



(1) Ovipara laying imperfect eggs. 



(2) Ovipara laying perfect eggs. 



10 (.3) OvoNipipara (Selacliia and vipers). 



(4) Tivipara. 

 12 (c) Further remarks on position of sexual organs. 



2 — Copidation of Bloodless Animals 



14 (a) Crustacea. 



15 (6) Cephalopods (including reference to the hectocotvlized 



arm of the Octopus). 



16 (c) In.sects : some (1) are generated by copulation, copulate, 



and produce larvae ; 

 some (2) are generated spontaneously, copulate, 



and produce larvae ; 

 some (3) are generated spontaneouslv and do 



not copulate. 



(1) includes locusts, cicadas, spiders, wasps, ants ; 



(2) fleas, flies, cantharides ; 



(3) gnats, mosquitoes, etc. 



3 — Theory of Sexual Generation 



17 (A) What is the nature of semen ? 



(a) Theory of "pangenesis" examined and refuted bv 

 various arguments. 



(b) Definition of semen : it is that " from " which natural 

 objects are produced. It is one of the " residues " — a 

 residue of the useful nourishment in its final form — 

 not a colliquescence. 



19 (B) Menstrual fluid. Tliis also is a residue, similar to semen, 

 but less concocted. It is the matter for generation. Since 

 the male p^o^^des the form, se\-eral offspring mav be 

 originated by one semen. 



21 (C) (a) Elaboration of the theory of generation. 



Ixxi 



