MORPHOLOGY OF EYE MUSCLE NERVES 6 



Civil war in the camp of the morphologists between anato- 

 mists and embryologists has led some to exclaim, "a, plague on 

 both your houses!" Morphology is the loser when embryolo- 

 gists and anatomists attack each other instead of morphological 

 problems. The pot has called the kettle black and the luster 

 of neither has increased. There seems to be no particular advan- 

 tage in discussing the question whether comparative anatomy 

 or embryology has been able to make the more valuable contri- 

 bution to the solution of morphological problems. It appears 

 not unreasonable to think that, notwithstanding frequent diver- 

 gence of theoretical conclusions, the key to the solution of mor- 

 phological problems lies in the hand of neither alone. The two 

 sciences must develop together. The results by one method need 

 to be 'controlled' by the other. * 



The elaboration of other than the annelid theory of vertebrate 

 ancestry upon which the orthodox conception has been largely 

 based, has tended to throw doubt upon the view that the seg- 

 mentation of the vertebrate head is an ancestral segmentation. 

 A morphologist of the last generation might have thought it 

 necessary to apologize for advocating the view that the verte- 

 brate head is an unsegmented portion of an unsegmented an- 

 cestor. No apology would be required today. As a matter of 

 fact, after a century of vertebrate morphology, we actually do 

 not know whether vertebrates came from a segmented or an 

 unsegmented ancestor; whether or not the present segmentation 

 in the head region is a true metamerism; whether the pre-otic 

 portion of the head is a coenogenetic addition to a primarily 

 segmented body, or a palingenetic remnant of an unsegmented 

 ancestor which has secondarily acquired a segmented trunk. 

 Even among those who agree that the present segmentation is 

 ancestral there is little accord as to the nature or number of 

 these somites. 



A grouping of morphological opinion, however, with reference 

 to the extremes of expression shows a strong tendency on the 

 part of morphologists to regard the head as metameric. The 

 curve of variation in opinion is decidedly skew in the direction 

 of morphological orthodoxy. Among the many papers dealing 



