1897] FOSSIL APODIDAE 401 



We have then, it seems to me, a simple and natural interpreta- 

 tion of the shape of the shield of Protocaris without assuming any 

 other distortion than that due to flattening. Had there been any 

 horizontal distortion, it would, one would expect, be more apparent 

 in the abdomen than in the shield. 1 am therefore disposed to look 

 upon Protocaris as an Apus in process of folding down laterally 

 its whole carapace, a modification which, as I have shown in some 

 detail elsewhere, 1 would lead on to the peculiar organisation of the 

 ostracods. I lay stress upon the word ' whole,' because if only the 

 free lateral flaps behind the head region are folded down, we 

 should get a form which might lead on to the other bivalve- 

 entomostraca, the Daphnidae and Estheridae. In making these 

 suggestions I am again taking up my original position that Apus is 

 the protonauplius of authors, and that from it or its young stages 

 all the Crustacea can be deduced. I may add indeed that nothing 

 which has been said during the last five years has shaken me in 

 that conviction, based originally upon my study of Apus. On the 

 contrary, all the new facts which have come to light have tended 

 without exception to confirm it. I refer mainly to the brilliant 

 researches of Beecher on the limbs of the Trilobite, Triarthrus, and 

 to these fossil Apodidae now under discussion. 



The whole question, however, must of course be decided solely 

 by the evidence ; hence, I may remark in passing, it is somewhat 

 surprising to find a zoologist declaring that he has no " sympathy 

 (sic) with the peculiar phylogenetic speculations of Bernard." Anti- 

 pathy against the views of a fellow-worker, however unscientific 

 such an attitude of mind may be, is perhaps excusable, but it is not 

 so excusable merely to refer readers to a semi-popular summary 

 and not to the papers containing the detailed evidence for the 

 hypothesis condemned. Readers could then judge for themselves 

 whether these ' peculiar phylogenetic speculations ' are speculations 

 at all, and not rather necessary deductions from established facts. 



Mr Schuchert's claim that ' eyes ' can be faintly seen on the 

 specimen will be noticed below. 



Dipeltls 



The claims of this fossil, of which only four specimens are known, 

 to belong to the Apodidae, seem to me far more intricate than are 

 those of Protocaris. It appears at first sight as if it might be a 

 transition form between Apus and the Trilobites, and yet it only (so 

 far as at present known) appears on the scene in the Lower 

 Carboniferous, when the Trilobites were already beginning to pass 

 away. 



] " Apodid.'e," Section xv., p. 252. 



