320 



ESSAY ON CLASSIFICATION. 



I. NUTRIENTIA. Warm-blooded Ver- 

 tebrata, taking care of their 

 young. 



CL. 1. MAMMALIA. 



CL. 2. BIRDS. 



A. Myeloncura. 

 II 



ORPIIANOZOA. Cold- blooded Ver- 

 tebrata, taking no care of 

 their young. 



CL. 3. AMPHIBIA. 



CL. 4. PISCES. 



B. Ganglioneura. 



A. Bphygmozoa, Cordata. 



Circulation marked by a heart 

 or pulsating vessels. 



III. ARTICULATA. Real articulation, 



marked by rows of ganglia 

 and their ramifications. 



CL. 5. INSECTS. 



CL. 6. ARACHNOIDEA. 



CL. 7. CRUSTACEA (including 

 Entomostraca, Cirripe- 

 dia, and Lernsea). 



CL. 8. ANNULATA. (The genu- 

 ine Annelids, exclusive 

 of Nais.) 



CL. 9. SOMATOTOMA. (Naidina.) 



IV. MOLLUSCA. No articulation. 



Ganglia dispersed. 



CL. 10. CEPHALOPODA. 



CL. 11. PTEROPODA. 



CL. 12. GASTEROPODA. 



CL. 13. ACEPHALA. 



CL. 14. BRACHIOPODA. 



CL. 15. TDNiCATA.(Ascidi0esim- 



plices.) 

 CL. 16. AGGREGATA. (Ascidue 



compositas.) 



B. Asphycta Vasculosa. 

 Vessels without pulsation. 



V. TUBULATA. No real articulation. 



Intestine, a simple sac or 

 tube. 



CL. 17. BRYOZOA. 



CL. 18. DIMORPH^EA. (Hydro- 

 ids.) 



CL. 19. TURBELLARIA. (Rhab- 

 doccela : Derostoma, 

 Turbella, Vortex.) 



CL. 20. NEMATOIDEA. (Entozoa, 

 with simple intestine ; 

 also Gordius and An- 

 guillula.) 



CL. 21. ROTATORIA. 



CL. 22. ECHINOIDEA. (Echinus, 

 Holothuria, Sipuncu- 

 lus.) 



VI. RACEMIFERA. Intestine divided, 



or forked, radiating, dendri- 

 tic, or racemose. 

 CL. 23. ASTEROIDEA. 

 CL. 24. ACALEPH^;. 

 CL. 25. ANTHOZOA. 

 CL. 26. TREMATODEA. (Ento- 

 zoa with ramified in- 

 testine, also Cercaria.) 

 CL. 27. COMPLANATA. (Dendro- 

 coela, Planaria, etc.) 



CL. 28. POLYGASTRICA. 



The system of Zoology published by Ehrenberg in 

 1836 presents many new views in almost all its pecu- 



