232 ESSAY ON CLASSIFICATION 



IV. Zoophytes. 

 Subbranch. Radiaria, or Radiata. 



Cl. Echinoderms. 



Cl. Acalephs. 



Cl. Corallaria, or Polypi. 



Subbranch. Sarcodaria. 

 Cl. Infusoria. 

 Cl. Spongiaria. 



CLASSIFICATION OF VON SIEBOLD AND STANNIUS 



This classification is adopted in the following work: Siebold and Stannius, Lehrbuch 

 der vergleichenden Anatoniie (2 vols., Berlin, 1845; 2d ed., 1855). 



EVERTEBRATA. 



I. Protozoa. 

 Cl. 1. Infusoria. Ord. Astoma and Stomatoda. 



Cl. 2. Rhizopoda. Ord. Monosomatia and Polysomatia. 



II. ZOOPHYTA. 



Cl. 3. Polypi. Ord. Anthozoa and Bryozoa. 

 Cl. 4. Acalephae. Ord. Siphonophora, Discophora, Ctenophora. 



Cl. 5. Echinodermata. Ord. Crinoidea, Asteroidea, Echinoidea, Holothurioidea, and 

 Sipunculoidea. 



III. Vermes. 



Cl. 6. Helminthes. Ord. Cystici, Cestodes,! Since the publication of the work quoted above, Sie- 

 rr-. ..J A ..I. uT>^j- • bold has introduced most important improvements in 



Trematodes, Acanthocephali, Gordiacei, > , , .^ . ^ , ,., ■ , ■ 



^ the cl^ssincation of the Worms, and greatly increased 



Nematodes. J ^^^ knowledge of these animals. 



Cl. 7. Turbellarii. Ord. Rhabdocoeli, Dendrocoeli. 

 Cl. 8. Rotatorii. Not subdivided into orders. 

 Cl. 9. Annulati. Ord. Apodes and Chastopodes. 



IV. Mollusca. 

 Cl. 10. Acephala. Ord. Tunicata, Brachiopoda, Lamellibranchia. 



Cl. 11. Cephalophora, Meek. (Gasteropoda.) Ord. Pteropoda, Heteropoda, Gastero- 

 poda. 

 Cl. 12. Cephalopoda. Not subdivided into orders. 



V. Arthropoda. 



Cl. 13. Crustacea. Ord. Cirripedia, Siphonostoma, Lophyropoda, Phyllopoda, Poecilo- 

 poda, Lajmodipoda, Isopoda, Amphipoda, Stomapoda, Decapoda, Myriapoda. 



Cl. 14. Arachnida. Orders without names. 



Cl. 15. Insecta. a. Ametabola. Ord. Aptera. b. Hemimetabola; Ord. Hemiptera, 

 Orthoptera. c. Holometabola. Ord. Diptera, Lepidoptera, Hymenoptera, Strepsiptera, 

 Neuroptera, and Coleoptera. 



VERTEBRATA. 



VI. Vertebrata. 



Cl. 16. Pisces. Subclasses: 1st. Leptocardii. 2d. Marsipobranchii. 3d. Elasmobranchii; 

 Ord. Holocephali, Plagiostomi. 4th. Ganoidei; Ord. Chrondrostei, Holostei. 5th. 



