REfiENT WORK ON THE PROTOCHORDA. 223 



Remarks on some Recent Work on the Proto- 

 chorda, with a Condensed Account of some 

 Fresh Observations on the Enteropneusta. 



By 

 Arthur Willey, M.A., D.Sc. 



The eighth volume of the well-known * Trait^ de Zoologie 

 Concrete/ by Professor Yves Delage and M. Edgard Herouard, 

 published in 1898, is devoted to what the authors style the 

 Procord^s or Prochordata, a group which is made to include 

 three classes, namely, Hemichordia, Cephalochordia, and Uro- 

 chordia. It is a pleasure to turn to a text-book in which the 

 Enteropneusta are treated on equal terms with the Cephalo- 

 chorda and the Urochorda, especially when, as in this case, 

 the distinguished authors have aimed at impartiality — a 

 quality which in one or two places has led them beyond the 

 bounds of discrimination. It goes without saying that the 

 work is an excellent one, and admirably calculated, on the 

 whole, to give a just idea of these animals ; but on the present 

 occasion I am neither concerned with its many excellences 

 nor with its few blemishes, but merely with the subject- 

 matter. 



No doubt the classification employed by the authors of this 

 text-book answers not only their purpose, but that of their 

 readers also. At the same time it should be borne in mind 

 that it is in no sense a final classification, nor even one which 

 corresponds to the present state of our knowledge. By not 

 including the Pterobranchia in the same volume with the 



VOL. 42, PART 2. NiilW SEllES. P 



