THE APODID^ PART I 



upon morphological, anatomical, and biological reason- 

 ing, the Apodidae deserve to take the place we assign 

 them as an almost ideal transition form between the 

 Annelida and the Crustacea. Here, as stated in the 

 Preface, we thought to leave the matter as an interest- 

 ing suggestion. Fortunately, however, we have the 

 means of testing the accuracy of our conclusions.. 



Admitting, on the one hand, that the confirmatory 

 evidence as to the truth of our theory given by the 

 Nauplius need by no means be conclusive, we maintain, 

 on the other hand, that the answer which we receive 

 to our appeal to palaeontology and to such archaic 

 living forms as Limulus must be decisive. Thus we 

 enter upon the second part of our essay in order to 

 obtain a final " yea " or " nay " as to whether our theory 

 is, as a whole, but a morphological tour de force, or a 

 fairly close guess at the truth. 



We commence with Limulus, and show that if Apus 

 is to be derived from an Annelid with the first five 

 segments bent round ventrally, Limulus must have 

 had a similar origin. 



In the second section we venture into the dangerous 

 realm of the Trilobites. The mystery which surrounds 

 these primitive Crustacea is so great, that every 

 announcement of a new discovery bearing upon their 

 morphology meets with more or less scepticism. 

 Nevertheless, we believe that we can prove that our 

 derivation of Apus from a bent Annelid reveals the 

 Trilobites also in their true light, as so many attempts 

 of browsing Crustacean-Annelids to adapt themselves 

 to their surroundings — attempts which, in the long 



