/OOLOGY. 



571 



multi-chambered calcareous shell, out of which they pro- 

 trude mucous filaments, and are therefore the antetypes 

 of the Corals or Polyps. 



3471. The Rotifera exhibit all kinds of viscera, such 

 as intestine and ovaries ; besides what have been called 

 rotatory organs, which remind us of the arms or tentacles 

 of the Acalephae. 



3472. The families of these animals may be therefore 

 aptly named as follows : 



Earn. 1. Typical Infusoria Monades ; cilia or vibratile organs. 



2. Polypary Infusoria Rhizopoda; extensible processes. 



3. Acalephan Infusoria Rotifera ; intestine and oral organs. 



Second Class. 

 Intestinal, Albuminous Animals Polypi. 



3473. The Polyps also do not admit of being divided 

 into more than three families. The first are only tubes 

 or vesicles with capillary tentacula around the mouth, as 

 the naked Polyps, Tubulariae, Serttilariae, and Cellulariae. 



The others have true ciliated tentacular rays sur- 

 rounding the mouth, and are always condensed inferiorly 

 into a horny, and occasionally stony axis or stem, as is 

 seen in the Gorgonise, Alcyonise, and Isidise. 



The third have ordinary tentacula, occurring in great 

 numbers like tassels or tufts around the mouth ; their 

 integument is either hardened into stone, or becomes 

 fleshy, as in the Star-corals and Actiniae. 



3474. There is no doubt that the naked Polyps are 

 closely allied to the Infusoria, and among them indeed to 

 the Rotifera, so that they represent but a higher stage of 

 these creatures, characterized by superior size and by 

 tentacular in place of ciliary or vibratile hairs. 



3475. The Cellular ice cannot be more distinctly cha- 

 racterized than by saying that they are cortices or rainules 

 inhabited by Vorticellae. Thus they are Vorticellae sur- 

 rounded by a shell, and may be compared to ova, in 

 whose coriaceous or leathery shell calcareous granules are 

 blended, as in the eggs of the Crocodiles and Tortoises. 



3476. They increase by means of ova and by ramifica- 

 tion, if the former mode of division is not carried too far. 



