DEGRADATION OF ORGANISATION 99 



of these animals and escape again, after having spread throughout 

 all their parts. 



Let it not be said that the isochronous movements of the soft radi- 

 arians are signs of respiration ; for nature does not exhibit in any 

 animal after the vertebrates those alternate and measured movements 

 of inspiration and expiration ; whatever the respiration of radiarians 

 may be, it is extremely slow and involves no appreciable movement. 



POLYPS. 



Animals with sub-gelatinous and regenerating bodies, with no special 

 organ but an alimentary canal with only one opening. Terminal 

 mouth supplied with radiating tentacles or a ciliated and rotatory 

 organ. 



With the polyps we reach the penultimate stage of the animal scale, 

 that is to say, the last but one of the classes which have to be established 

 among animals. 



Here the imperfection and simplicity of organisation are very 

 striking, so that the animals of this group have scarcely any faculties 

 left, and their animal nature has long been doubted. 



They are gemmiparous animals with homogeneous bodies, usually 

 gelatinous, and with very regenerative parts, not displaying the 

 radiating shape (for it is only here that nature began it) except in 

 radiating tentacles around their mouth, and having no special organ 

 but an intestinal canal, which has only one opening and is therefore 

 incomplete. 



The polyps may be described as much more imperfect animals 

 than any of those which make up the preceding classes, for they have 

 no brain, longitudinal cord, nerves, special respiratory organs, vessels 

 for the circulation of fluids nor ovary for reproduction. The substance 

 oF their body is to a great extent homogeneous and composed of 

 a gelatinous and irritable cellular tissue in which fluids move slowly. 

 Lastly, their viscera are entirely reduced to an imperfect alimentary 

 canal, rarely folded on itself or provided with appendages, and usually 

 resembling a mere elongated sac, always with a single opening which 

 serves at once for mouth and anus. 



There can be no justification for the statement that, although 

 we find in these animals no nervous system, respiratory organ 

 or muscle, etc., yet these organs still exist infinitely reduced and 

 distributed or dissolved throughout the general substance of the 

 body, and equally divided up in every molecule instead of being 

 collected in special places ; consequently that every point in their 



