aOLDSOHMIDT S MONOGRAPH OP AMPHIOXIDES. 595 



vein^ is displaced to the right side. In front of the pharynx 

 the branchial artery bends up more dorsally and ends 

 blindly, co-extensive with the aorta and the prseoral gut. 



One word concerning the classification adopted by Dr. 

 Goldschmidt. He only recognises two genera of Branchio- 

 stomidse, namely, Branchiostoma, Costa, 1834, and 

 Epigonichthys, Peters, 1876. Opinion may be reserved 

 regarding the necessity of abolishing certain other generic 

 terms which have been introduced, but the resuscitation of 

 Epigonichthys is clearly correct. 



A great deal more information is contained in Dr. 

 Goldschmidt's monograph than what I have outlined above. 

 In order to render the presentation of the portion of his 

 theoretical excursions which I have selected for criticism 

 more complete, it should be added that he traces the origin 

 of what he considers to be the primitive condition of the 

 pharynx as determined by the ventral series of gill-slits, to 

 the secondary extension of the segmental musculature towards 

 the ventral side ; this circumstance (and here he is in agree- 

 ment with Boveri) would also account for the existence and 

 peculiar method of development of the atrial chamber of 

 Amphioxus. It may be admitted that there is very likely a 

 good deal of truth in this correlation when regarded from the 

 point of view of the mechanical conditions of development, 

 without prejudicing supposed morphological or phylogenetic 

 relations one way or the other. 



By the courtesy of the Cambridge University Press^ I am 

 able to reproduce a set of diagrams which may serve a useful 

 purpose as indicating different points of view, and thus 

 helping to clear the issues. 



In a recent article Professor van Wijhe^ states that I have 



1 ' Zoological Results ' (A. Willey), part vi, 1902, p. 728. The matter is 

 introduced into that portion of my "Contribution to the Natural History of 

 the Pearly Nautilus," which is devoted to " Personal Narrative." I take this 

 opportunity of noting an unfortunate misprint on page 800 of that publication, 

 where the word "Branchial" should have been "Brachial." 



^ J. W. van Wijhe, " Die Homologisirung des Mundes des Ampliioxus und 

 die primitive Leibesgliederung der Wirbelthiere," 'Petrus Camper,' April, 

 1906, p. 17 of reprint. 



