CHAPTER II. 

 CLASSIFICATION. 



THE following classification includes only the forms 

 mentioned in the succeeding pages. The relative value of 

 some of the terms employed in classification is not identical 

 throughout the book. This remark applies specially to the 

 term group, which is a convenient one, owing to its not having 

 such a hard and fast zoological meaning as has the term family, 

 for instance. The term group is applied in this book to 

 divisions of the animal kingdom of very different classificatory 

 importance. 



PHYLUM CHORDATA. 



SUBPHYLUM A. HEMICHORDATA. 



Balanoglossus. 

 Cephalodiscus. 

 Rhabdopleura. 

 1 Phoronis. 



(? Actinotrocha larval Phoronis). 



% 



SUBPHYLUM B. UROCHORDATA (TUNICATA). 

 Group LARVACEA and others. 



SUBPHYLUM C. CEPHALOCHORDATA. 



Amphioxus laricelet. 



NOTE. In this chapter all the generic names printed in italics are 

 those of extinct animals. 



