XVI 



PEEFACE. 



my exiDerience as teacher and examiner has shown me that English students 

 are thoroughly familiarised. 



BUB-KINGDOMS. 



Protozoa. 



(Ehizopocla, Gregaiinida, 

 Eadiolaria, Spongida.) 



Infusoeia. 



ccelenterata. 



(Hydrozoa, Ac^inozoa.) 



Annulolda. 



(Scolecida, Echinoderma.) 



Annulosa. 



(Crustacea, Arachnida, 

 Myi-iapoda, Insecta, Chtc- 

 tognatha, Annelida.) 



MOLLUSCOIDA. 



(Polyzoa, Braohiopoda, 

 Tunicata.) 



MoLLt'SCA. 



(Lamellibrauchiata, Brau- 

 chiogastropoda, Pulmo. 

 gastropoda, Pteropoda, 

 Cephalopoda.) 

 Vertebrata. 



(Pisces, Amphibia,ReptiliQ, 

 Aves, Mammalia.) 



II. 



PHYLA. 



Protozoa.* 



III. 



PHYLA. 



Protozoa.* 



CfELEXTEEATA. 

 VERMES.f 



Echinoderma. 



BRACHioronA.J 



Arthropoda. 



Mollusc A. 



Tunicata.§ 



Vertebrata. 



porifera. 



Nematopiiora. 



i'f ^ ^ 



Platyhelmia.|| 



Gepiiyrea.|| 



Echinoderma. 



Enteropneosta.II 



Nematoidea. II 



Ohjstognatha.II 



Appendiculata.^ 



mollusca.** 



Vertebrata. ff 



Seeing that one of my chief objects in superintending the translation of 

 the-treatise to which these few pages are introductory, has been to be able 



* The Protozoa in Nos. II. and III. include the same organisms as iu No. Ir, 

 excepting that the Infusoria are included in that phylum in Nos. II. and III., and that 

 the Sponges are excluded, being in No. II. placed under the Coelenterata, and in 

 No. III. fomiing the phylum Porifera under the " grade " Coelentera, as shown in the 

 genealogical tree on the adjacent page. 



t The Vermes of No. II. include all the Annuloida of No. I. excepting the 

 Echinoderma, which are raised to the rank of an independent phylum. They also 

 include the Annelida (Chsetopoda, Hirudinea, and Gephyrea) from amongst the 

 Anuulosa of No. I. and the Polyzoa from amongst the MoUusco'ida of the same series. 



X The Brachiopoda, raised to the position of a distinct phylum in No. II., are 

 placed among the MoUusco'ida in No. I. and amongst the MoUusca in No. III. 



§ The Tunicata, considered as an independent phylum in No. II., are found 

 amongst the Molluscoida in No. I. and form a section of the Vertebrata in No. III. 



II The Platyhelmia, Gephyrea, Enteropneusta, Nematoidea, and Chaetognatha 

 form in No. III. a number of independent phyla. Together with the Polyzoa 

 (included in No. III. under the Mollusca), the Rotifera. and the Chjetopoda, included 

 under the Appendiculata, they constitute the .series of phyla which are in No. II. 

 massed together as " Vermes." 



^ The Appendiculata include animals with lateral locomotive appendages, and 

 nsually a segmented body. The group is, excepting thai it has the addition of the 

 Rotifera, nearly co-extensive with the Annulosa of No. I. 



** The phylum Mollusca in No. III. includes the Polyzoa and Brachiopoda, 

 excluded from it iu both No. I. and No. II. 



ft The Vertebrate phylum in No. Ill, includes the Tunicata, which it will be seen 

 by reference to page 70 are already placed on the Vertebrate stem by Professor 

 Gegenbaur, 



