ANATOMICAL SYSTEMS. 333 



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 1 adopted 

 by von Siebold and Stannius, I have nothing to remark 

 that has not already been said. 



CLASSIFICATION OF R. LEUCKART. 



The classification of Leuckart is compiled from the following work : LEOCK- 

 ART (R.), Ueber die Morphologic und die Verwandtschaftsverhiiltnisse der 

 wirbellosen Thiere ; Braunschweig, 1848, 1 vol. 8vo. 



I. COELENTERATA, Lkt. 



CL. 1. POLYPI. Ord. Anthozoa and Cylicozoa (Lucernaria). 

 CL. 2. ACALEPH.E. Ord. Discophorse 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. Holothurise and Sipunclida. 

 III. VERMES. 



CL. 6. ANENTERATI, Lkt. Ord. Cestodes and Acanthocephali. (Hel- 



minthes, Barm.) 

 CL. 7. APOPES, Lkt. Ord. Nemertini, Turbellarii, Trematodes, and 



Hirudinei. (Trematodes, Jjurm.) 

 CL. 8. CILIATI, Lkt. Ord. Bryozoa and Rotiferi. 

 CL. 9. ANKELIDES. Ord. Nematocles, Lumbricini, aud Branchiati. 



(Annulati, Burm., excl. Nemertinis et Hirudineis.) 

 IV. ARTHROPODA. 



CL. 10. CRUSTACEA. Ord. Entoinostraca (Neusticopoda Car.) and 



Malacostraca. 

 CL. 1 1. INSECTA. Orel. Myriapoda, Arachnida (Accra, Latr.) and 



Hexapoda. 

 V. MOLLUSCA, Cuv. (Palliata, Nitzsch.) 



_ , . .,. -\ Leuckart is somewhat inclined to 



CL. 12. TUNICATA. Ord. AsCldiae consider the Tuuicata, not simply as 

 (Tethyes Sav.) and Salpae ', aclass,buteven as another great type 

 fThalides Sav ^ or branch, intermediate between Echi? 



J noderms and Worms. 



1 The names of the types, Proto- various ways for nearly half a cen- 



zoa and Vermes, are older than their tury ; while that of Worms was first 



limitation in the classification of Sie- adopted by Linnseus, as a great divi- 



bold. That of Protozoa, first intro- siou of the animal kingdom, but in a 



duced by Goklt'uss, has been used in totally different sense. 



