358 Dr Barry on the Unity of' Structure 



tively, the points reached in the development of a male and 

 female of a species, in which the sexual organs are very simple, 

 and in which, therefore, the sexual difference is very small. 

 It is plain, that a deviation here, would be more appreciable, 

 because relatively greater, than if development had pro- 

 duced complicated structures, and carried the sexes further 

 apart, as, for example, to the points KL : in other words 

 the less the angle of divergence, the more appreciable is a 

 deviation, and therefore the more " complete" is the herma- 

 phrodism. 



But, " in proportion as the genital organs are simple, and in 

 proportion as they resemble each other in the normal state," 

 when perfect, the less pronounced must be the reference to 

 them throughout development ; the later therefore do they ma- 

 nifest themselves. Now, as already said, the liability of parts 

 to malformation, is in the direct ratio of their lateness in de- 

 velopment. Hence, in such cases, the more " frequent" is her- 

 maphrodism. 



We conclude, then, that the explanation before offered, re- 

 garding the necessity of a modified re-appearance in individual 

 development, of structures common to a whole class of animals, 

 and regarding the order of such re-appearance, is applicable 

 to all congenital anomalies, including those called fct herma- 

 phrodites." 



It remains to notice unity of plan, as obvious in organs of 

 the same organism ; various parts appearing like modified copies 

 of each other. Organs of the same organism that admit of such 

 comparison, being among those that originate in the same la- 

 mina of the germinal membrane or tube, analogies appear refer- 

 able, \stly> to a common origin, and therefore 2c?&/, to a com- 

 mon fundamental and general form, some resemblance, 3dly, 

 being preserved in proceeding towards the special. 



A diagram used in our former memoir being required here, 

 we again introduce it, to save reference.* Let the point A, 



* For a more detailed application of the elements of this diagram, see pages 

 135, 136, of the last number of this Journal. 



