Animal Morphology. 95 



To come to the long-deferred point, the ganglionic 

 tripartite membrane consists of three parts : 



Firstly : The ganglia, as the cervical, prevertebral or 

 thoracic, the solar plexus, and the greater and lesser 

 splanchnic plexuses, etc., etc. 



Secondly : The branches, or communicating fibres. 



Thirdly : The muscular membrane, which membrane 

 consists of the heart and the organic muscular fibres termina- 

 ting arteries, or the capillary termination of arteries. 



The ganglia are viewed as the glandular or mucous 

 membrane perverted, yet in its differentiation retaining its 

 function, but perverted in its physical character in toto. 

 The communicating fibres are serous membrane in function ; 

 and the heart and capillary muscular fibres are the true 

 contractile membrane belonging to the ganglionic system. 



The enormity of this morphological change and displace- 

 ment will be greatly questioned; probably it will be the point 

 at which many will say we can no longer go with such 

 extravagances. 



But, strange as this explanation may appear, it is more 

 than probable that it is abstractedly correct. For if we 

 take into consideration that the lower forms of the subver- 

 tebrata have no real heart, neither have they any lacteo- 

 lymphatic system, nor yet ganglionic system, the feeble 

 circulation and the power through imbibition and exosmosis, 

 especially where the circulation is feeble and slow, need no 

 complicated system of elaborate digestion or conversion of 

 aliment into blood, nor yet any complex and perfectly 

 rhythmical and systematic form of carrying on the distribu- 

 tion of aliment ; or a beautiful system for removing and 

 economising of old and used-up material ; but in higher life 

 these complex systems are essential to the well-being of the 

 individual, and cannot be well dispensed with. 



The first question that arises is, Why should the heart 



