140 



Correspondence . 



r Emu 

 L2nd Ocl 



The following diagrams roughly illustrate my suggestioi 



Fig 



Formula of the two Eggs (A and B), Fig. i. 



3 4 5123 4 



be d a h c d 



\ 



Fig. 



■75 L 



Terminology. 



Points of an Egg. 

 Base. 



Zonal point. 

 Diametral point. 

 Sub-apical point. 

 Apex. 



Areas of an Egg. 

 (a) Basal. 

 (h) Zonal. 



(c) Sub-apical. 



(d) Apical. 



The Method of Measuring and Dividing for Description. 



Fig. I. — Ascertain the distance of the greatest diameter from 

 the larger end (base) of the egg, from which point all measure- 

 ments are to be made, and make this point (3) the axis of division 

 for the intermediate points 2 and 4. The point 2 is exactly half- 

 way between i and 3, and the point 4 is half-way between 3 and 

 5. Thus, we have the egg with five points (i, 2, 3, 4, and 5) and 

 four spaces [a, h, c, d), which we can designate as areas, and 

 which are to be used for the purposes of description. 



Fig. 2. — These are lines to represent the exact lengths of the 

 eggs (Fig. I, A and B), and intersected to indicate where the 

 measurements of diameters are made (A and B, Figs, i, 2, 3, 4). 

 These lines, or formulae, can be printed with the descriptions, and 

 thus convey a definite idea of the lengths and various diameters 

 of the eggs from which they were made. The areas a, b, c, d 

 (Fig. I, A and B), are represented in the formulae by the same 

 letters. The numlDers 2, 3, and 4 indicate the respective diametral 

 measurements, and are placed above the line, with their actual 

 measurements under the line, and opposite to them. The object 

 of measuring from the larger end is to meet specimens like 

 Orthonyx spaldingi, so that where the diametral point is made, 

 the intermediate point 4, or sub-apical point, is in a position to 

 show the degree of tapering towards the apex. 



In The Emu, vol. ix., part 3, page 136, S. W. Jackson gives a 



