546 G. C. BOURNE. 



tionally called an archiccele, i. e. it is derived from the original 

 segmentation cavity, as is the cavity of the head in all Anne- 

 lids. It is possible that this statement may be extended to 

 all other Annelids in which the coelom is stated to result from 

 the splitting of the mesoblast into somatopleure and splanch- 

 nopleure, but against the probability of this view must be set 

 the careful researches of Hatschek. 



Finally, it is gratifying to find that Kleinenberg has insisted 

 upon the intimate connection between morphology and phy- 

 siology. Enough has been said in the foregoing pages to show 

 how strongly he insists upon the dependence of function upon 

 form. In the introductory chapter he condemns the theory of 

 the Hertwigs, that the origin of cells can be predicated by their 

 form, and shows from numerous examples that the form of 

 cells is caused solely by their function and the mechanical 

 necessities of their position. Naturally the two formative 

 conditions, position and function, generally coincide ; but if 

 there is a contention between those conditions, function 

 prevails. 



In an abstract which has to be confined within certain limits 

 of space, I am unable to give more than the most meagre 

 outline of Prof. Kleinenberg's argument. It is enough, how- 

 ever, if I have succeeded in calling attention to his remarkable 

 work, and in inducing morphologists to read carefully the 

 formidable paper in which his results are published. 



