PRINCIPAL SYSTEMS OF ZOOLOGY 233 



Teleostei; Ord. Acanthopteri, Anacanthini, Pharyngognathi, Physostomi, Plectognathi, 

 Lophobranchii. 6th. Dipnoi. 

 Cl. 17. Reptilia. Subclasses: 1st. Dipnoa; Ord. Urodela, Batrachia, Gymnophiona. 

 2d. Monopnoa: a. Streptostylica; Ord. Ophidia, Sauria. b. Monimostylica; Ord. Chel- 



onia PrnrnflilT ^ The subdivisions of the classes Pisces and Reptilia are taken from the second 



f> jQ A L edition, published in 1854-1856, in which J. Miiller's arrangement of the Fishes 



/-^ in »» ' !• I is adopted; that of the Reptiles is partly Stannius's own. The classes Avca and 



CL. ly. Mammalia. J Mammalia, and the first volume of the second edition, arc not yet out. 



The most original feature of the classification of von Siebold is 

 the adoption of the types Protozoa and Vermes, in the sense in which 

 they are limited here. The type of Worms has grown out of the in- 

 vestigations of the lielminthologists, who, too exclusively engaged 

 with the parasitic Worms, have overlooked their relations to the 

 other Articulata. On the other hand, the isolation in which most en- 

 tomologists have remained from the zoologists in general has no 

 doubt had its share in preventing an earlier thorough comparison of 

 the Worms and the larval conditions of Insects, without which the 

 identity of type of the Worms, Crustacea, and Insects can hardly be 

 correctly appreciated. Concerning the classes^^ adopted by von Sie- 

 bold and Stannius I have nothing to remark that has not been said 

 already. 



CLASSIFICATION OF R. LEUCKART 



The classification of Leuckart is compiled from the following work: Leuckart, Ueber 

 die Morphologie und die Verwandtschaftsverhliltnisse der ivirbellosen Thiere (Bruns- 

 wick, 1848). 



I. COELENTERATA, Lkt. 



Cl. 1. Polypi. Ord. Anthozoa and Cylicozoa (Lucernaria.) 

 Cl. 2. Acalephae. Ord. Discophorae and Ctenophorae. 



II. ECHINODERMATA, Lkt. 



Cl. 3. Pelmatozoa, Lkt. Ord. Cystidea and Crinoidea. 



Cl. 4. Actinozoa, Latr. Ord. Echinida and Asterida. 



Cl. 5. Scytodermata, Brmst. Ord. Holothuriae and Sipunculida. 



III. Vermes. 

 Cl. 6. Anenterati, Lkt. Ord. Cestodes and Acanthocephali. (Helminthes, Burm.) 

 Cl. 7. Apodes, Lkt. Ord. Nemertini, Turbellarii, Trematodes, and Hirudinei. (Trema- 



todes, Burm.) 

 Cl. 8. Ciliati, Lkt. Ord. Bryozoa and Rotiferi. 

 Cl. 9. Annelides. Ord. Nematodes, Lumbricini, and Branchiati. (Annulati, Burm,, 



excl. Nemertinis et Hirudineis.) 



"The names of the types. Protozoa and Vermes, are older than their limitation in 

 the classification of Siebold. That of Protozoa, first introduced by Goldfuss, has been 

 used in various ways for nearly half a century, while that of Worms was first adopted 

 by Linnaeus as a great division of the animal kingdom but in a totally different sense. 



