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ESSAY ON CLASSIFICATION.
Cl. 7. Turbellarii. Ord. Rhabdoeoeli, Dendrocceli.
Cl. 8. Rotatorii. Not subdivided into orders.
Cl. 9. Annulati. Ord. Apodes and Chsetopodes.
Cl. 10. Acephala. Ord. Tunieata, Brachiopoda , Lamellibranchia .Cl. 11. Cephalophora, Meek (Gasteropoda ). Ord. Pteropoda, He-teropoda, Gasteropoda .
Cl. 12. Cephalopoda . Not subdivided into orders.
V. Arthropoda.
Cl. 13. Crustacea. Ord. Cirripedia, Siphonostoma, Lophyropoda,Phyllopoda, Poecilopoda, Lsemodipoda, Isopoda, Amphipoda,Stomapoda, Decapoda , Myriapoda .
Cl. 14. Arachnida . Orders without names.
Cl. 15. Insecta. a. Ametabola. Ord. Aptera. b. IIemimetabola.
Ord. Ilemiptera, Orthoptera . c. Holometabola. Ord.Diptera , Lepidoptera , Hymenoptera , Strepsiptera, Neuro-ptera, and Coleoptera .
Cl. 16. Pisces. Sub-classes : 1st. Leptocardii. 2nd. Marsipo-eranchii. 3rd. Elasmobranchii ; Ord. Holoeephali, Pla-giostomi. 4th. Ganoibei ; Ord. Chrondrostei, Holostei.5th. Teleostei ; Ord. Acanthopteri , Anacanthini , Pharyn-gognathi, Physostomi, Plectognathi, Lophobranchii. 6th.Dipnoi .
Cl. 17. Reptilia . Sub-classes: 1st. Dipnoa ; Ord. Urodela , Ba-trachia, Gymnophiona. 2nd. Monopnoa : a. Streptosty-liea; Ord. Ophidia, Sauria. b. Monimostylica; Ord. Che-
The sub-divisions of the classes Pisces and Rep tilia are taken from the second edition, published in1854-50, in which J. Muller’s arrangement of theFishes is adopted; that of the Reptiles is partly Stan-nius’ own. The classes Aves and Mammalia , andthe first volume of the second edition, are not yet out.
J
The most original feature of the classification of vonSiebold is the adoption of the types Protozoa and Yermes,in the sense in which they are limited here. The typeof Worms has grown out of the investigations of the hel-minthologists, who, too exclusively engaged with the para-sitic Worms , have overlooked their relations to the otherArticulata. On the other hand, the isolation in whichmost entomologists have remained from the zoologists in