Church. — The Principles of Phyttot'axis. 243 



factory, it adds considerably to the completeness of the principles of proto- 

 plasmic segmentation, and may be extended in several directions with 

 further interesting results. It is only necessary to point out that the case 

 of centric-growth is after all only a first step ; and the most elaborate 

 growth forms of the plant-kingdom, as exhibited for instance in the seg- 

 mentation of the leaf-lamina, may be approached along similar lines, and 

 by means of geometrical constructions which are consequent on the more or 

 less perfect substitution oi eccentric and ultimately wholly unilateral growth- 

 extension, which again must ever be of a retarded type. The subject thus 

 rapidly gains in complexity ; but that the study of growth-form, which 

 after all is the basis of all morphology, must be primarily founded on such 

 simple conceptions as that of the ' growth-centre ' which has here been put 

 forward, should I think receive general assent, and in the case of the quasi- 

 circle, there can be little doubt as to the extreme beauty of the results 

 of the mathematical consideration. 



