154 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
of a perfect ellipsoid, are somewhat in excess of the true values. The 
capacity of all the other eggs was found by weighing them when filled 
with water, and reducing the results; hence the table can be relied 
upon as being more accurate than that based upon the computations of 
Geoffrey St.-Hilaire.’ 
This author asserts that the egg of pyornis is equal in capacity to 
6 ostrich eggs, or 12 of the nandu, 16.5 of the cassowary, 17 of the emeu, 
or 148 of the common fowl, assuming the latter to hold on the average 
60 c.cm. One arbitrary standard is as good as another, and, as the hen’s 
egg for which measurements are given (No. 19 of the table) happened 
to contain exactly 50 ¢c.cm., we may adopt it as our unit; whence it 
appears that a medium-sized emeu’s egg is equal to 7 such units ; a casso- 
wary’s (C. bennetti) 11; a nandu’s 10 to 12; an ostrich’s 27 ; a moa’s 84; 
and the largest known ‘Aigyoress egg no less than 220. It may be wae 
mentioning in this connection, for the benefit of those interested, that 
the eggs of Zpyornis and Dinornis have been sold at prices ranging 
between £100 and £200, and the price asked for the type of Struthio- 
lithus equals about $770 of our money. These fabulous prices are de- 
pendent, of course, upon the scarcity of the objects; for although egg 
fragments of the two first named genera are tolerably abundant, the 
number of perfect specimens all told is Jess than a score. 
But to return to the description of Struthiolithus. It is probable that 
the egg shell was only partially embedded in the soil when found, the 
evidence for this being that the greater portion of the surface is in- 
crusted, more or less granulated, and otherwise affected by atmospheric 
erosion. The least weathered side is that shown in Figure 2, on which 
several areas are to be observed where the original shell has remained 
unaltered. Some discoloration has been brought about through the 
agency of iron oxide, and grains of ferruginous sand still adhere to the 
shell in places, or are even partially embedded in the crust. This side 
of the shell is of a brownish yellow color, somewhat darker than the 
opposite or more weathered side, shown in Figure 1. Numerous fine 
pittings are to be seen over the greater part of the periphery, some of 
which may be due to destructive agencies, but the majority of them are 
clearly to be regarded as the round terminal pores of air canals. To 
1 Comptes Rendus, Vol. XXXII. (1851), p. 102. Cf. also Comptes Rendus, 
Vols. XX XIX. (1858), p. 833, and LXV. (1864), p. 476; Proc. Zoolog. Soc. London, 
1852, p. 9, and 1867, pp. 892-991; Ibis, [2], Vol. IV. (1868), p. 65; Ornithological 
Miscellany (G. D. Rowley), Vol. III. p. 237 (1878) ; Owen’s Extinct Wingless 
Birds of New Zealand, Vol. I. pp. 817-820 (1879). 
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