520 PROFESSOR DICKSON ON SOME ABNORMAL CONES OF PINUS PINASTER. 



Figure 9. Cone, from Mr Smyth, Emyvale ; considerably reduced (natural size 4 J inches). This cone 

 exhibits a very regular spiral of the series £, \, § , T \, &c. It will be seen that the lines 

 by 37 are scarcely vertical, so that the spiral has probably the divergence £f . 



[Plates XXI. and XXII. The diagrams or plans here hardly require explanation. The regions 

 exhibiting the different spiral arrangements are marked off from each other by horizontal lines projecting 

 laterally at the level where each new system commences ; the arrangement in each region being 

 indicated by a fraction alongside of it. I have marked the " scales of convergence " with their number 

 in the upper of the two systems in the respective cases ; adding, within brackets, the numbers of the 

 actual or presumed components of these scales according to the spiral of the lower system, — the actual 

 without, the presumed with, a mark of query.] 



Plate XXI. 



Figure 1. Diagram of Cone I. It will be noted that here, in order to save room, the uppermost spiral 

 is carried up only to No. 36 of the 106 or 107 scales in the corresponding region of the 

 cone. 



Figure 2. Diagram of Cone II. 



Plate XXII. 



Figure 1. Diagram of Cone III. 

 Figure 2. Diagram of Cone IV. 



