16 



LECTURE II. 



Kingdom ANIMALIA. 



Sub-kingdom VERTEBRATA. 



Class Mammalia. 



AVES. 



Reptilia. 

 Pisces. 

 Sub-kingdom ARTICULA TA. Sub-kingdom MOLL USCA, 



Class Crustacea. Class Cephalopoda. 



Arachnida. Gasteropoda. 



Insecta. Pteropoda. 



Anellata. Lamellibranchiata. 



Cirripedia. Brachiopoda. 



Tunicata. 

 Sub-kinsdom RADIATA. 



Nematoneura. 



Acrita. 



Class II ad I ARIA, Lamarck. 



Echinoderma, Cuv. 



AcALEPHA, Cuv. 



Class Polypi, Cuv. 



Ciliobrachiata, Farre. Anthozoa, Ehrenb. Nudibrachiata, 



Farre. 

 Class Entozoa, Rudolphi. 



Coslelmintha, Owen. Sterelmintha, Owen. 



Class Infusoria, Cuv. 



Rotifera, Ehrenb. 



Polygastria, Ehrenb. 



LECTURE II. 



POLYGASTRIA. 



I PROPOSE first to invite your attention to a class of animals, the most 

 minute and apparently the most insignificant of created beings. It 

 might almost seem needful to apologise for the design of trespassing 

 on your time and patience during one or two lectures with the 

 Anatomy and Physiology of creatures which are wholly invisible to 

 the naked eye. But we are too apt to let our judgments of the im- 

 portance of objects be unduly influenced by first impressions, espe- 

 cially by those of magnitude or the contrary, Avhich deeper insight 

 into their true nature and value rectifies. 



The active atoms about to be described, for the knowledge of whose 



