APPENDIX II 



CLASSIFICATION OF THE CHORD ATA 



The following classification includes the living classes and 

 orders of the Chordates, and the fossil orders which are con- 

 sidered most important. All fossil groups are indicated with an 

 asterisk (*). In an effort to indicate equivalence of phylo- 

 genetic rank it is often necessary to group animals into Super- 

 classes, Super-orders, or Super-families. Division or Grade are 

 also used to show such relative positions. Although this is un- 

 doubtedly the more scientific procedure, there is frequently a 

 lack of agreement among taxonomists; therefore, for simplicity, 

 these divisions are used as little as possible in this scheme of 

 classification. 



With the exception of the Order Primates, which is classified 

 to family, only a few of the more important families of the 

 vertebrates are included. The basis of selection is the need of 

 the student in his laboratory work, rather than scientific im- 

 portance. 



PHYLUM CHORD ATA 



Sub-phylum I. HEMICHORDATA 



Class 1. Enteropneusta [Balanoglossiis, and other 



"Acorn Worms"). 

 Class 2. Pterobranchia (Two little known genera). 

 Sub-phylum II. UROCHORDATA 



Class 1. TuxiCATA (Tunicates). 

 Sub-phylum HI. CEPHALOCHORDATA 



(Contains only a few genera, including Amphioxus lan- 

 ceolatus). 



357 



