302 



PHILOSOPHICAL NOTES ON 



an unfolding of dormant vigour, and complexity, awakening new 

 forms, are going on in another direction — tlie wliole with a 

 wonderful elasticity of parts, ever suiting itself to new sur- 

 roundings. Nevertheless, the force of heredity is often so strong, 

 that it is ever restraining the tendency to change. It thus often 

 jirevents a degraded organ from becoming wholly extinct. How- 

 ever useless it may have become on the old lines, new uses are 

 often found for it on other lines as a helper in the great 

 struggle. 



To show that there is foundation for considering the oil glands 

 of the Citrus of cryptogamic origin, we shall have to dive down to 

 the lower strata of the veo-etahle kingdom. There we shall find 

 the genus Fucus, in which Lindley (" V. K.," p. 22«), quoting from 

 Thuret, says, " The fructification is contained in little spherical 

 cavities situated beneath the epiderm, and called conceptacles. 

 Completely closed at Jirst (note this) the conceptacles open 

 eventually at the surface of the frond by a little pore or mouth 

 through which the reproductive bodies escape.* Their exit is 



P'ip. 129. Frond of Myriodesma latifolia (" Harv. Phyc. Austr./' pi, 24) 

 dotted Avith fertile conceptacles : («) enlar<fed conceptacle, showino- spores 

 and antherides. 



* In my opinion these conceptacles do not differ morphologically from 

 the soil of ferns. The latter are on the snrface, the former are embedded 

 in the substance of the frond. Some seaweeds have their conceptacles on 

 the surface, like sort. 



