PRINCIPAL SYSTEMS OF ZOOLOGY 223 



to remove some incorrect names; but he extended his reform too far 

 when he undertook to change those also which did not suit his sys- 

 tem. 



CLASSIFICATION OF EHRENBERG 



The characteristics of the following twenty-eight classes of animals, with a twenty- 

 ninth for Man alone, are given more fully in the Transactions of the Academy of Berlin 

 for 1836.^ 



1st Cycle: Nations. Mankind, constituting one distinct class, is characterized by the 

 equable development of all systems of organs, in contradistinction of the 

 2d Cycle: Animals, which are considered as characterized by the prominence of single 

 systems. These are divided into: 



A. Myeloneura. 



I. NuTRiENTiA. Warm-blooded Vertebrata, taking care of their young. 

 Cl. 1. Mammalia. 

 Cl. 2. Birds. 

 II. Orphanozoa. Cold-blooded Vertebrata, taking no care of their young. 

 Cl. 3. Amphibia. 

 Cl. 4. Pisces. 



B. Ganglioneura. 



A. Sphygmozoa, Cordata. 

 Circulation marked by a heart or pulsating vessels. 



III. Articulata. Real articulation, marked by rows of ganglia and their ramifications. 

 Cl. 5. Insecta. 



Cl. 6. Arachnoidea. 



Cl. 7. Crustacea (including Entomostraca, Cirripedia, and Lernaea.) 

 Cl. 8. Annulata. (The genuine 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. Tunicata. (Ascidiae simplices.) 



Cl. 16. Aggregata. (Ascidiae composite.) 



B. Asphyeta, Vasculosa. 

 Vessels without pulsation. 



V. TuBULATA. No real articulation. Intestine, a simple sac or tube. 

 Cl. 17. Bryoroa. 



Cl. is. Dimorph a. (Hydroids.) 



Cl. 19. Turbellaria. (Rhabdocoela: Derostoraa, Turbella, Vortex.) 

 Cl. 20. Nematoidea. (Entozoa, with simple intestine; also Gordius and Anguillula.) 

 Cl. 21. Rotatoria. 



Cl. 22. Echinoidea. (Echinus, Holothuria, Sipunculus.) 

 VI. Racemifera. Intestine divided, or forked, radiating, dendritic, or racemose. 

 Cl. 23. Asteroidea. 



^ [In XIV, 605. See also Das Naturreich des Menschen (1835).] 



