EGGS i89 



In regard to the almost countless cases of spotted eggs in holes 

 or covered nests, of which so many groups of birds fm-nish 

 examples either Avholly or in part, the only supposition that could 

 apparently justify the last statement would be that the species 

 in question have taken to hiding their treasures in times compara- 

 tively recent, and have not yet got rid of the ancestral habit of 

 secreting and depositing pigment. In support of such an argument 

 might be alleged, among some other cases, the generally pale colour- 

 ing of eggs of the Daw, Corvus mojiedula, compared with those of its 

 kindred, as indicating a step in this direction, while a more con- 

 clusive one has been taken by those members of the Hlrundinidai as the 

 Sand-Martin, Cotile riparia, and House-Martin, Chelidon urbica, which 

 breed in holes or build close nests — their relative the Swallow, 

 Hinindo rustica, though its nest is rarely exposed to direct light, con- 

 tinuing to lay eggs that are conspicuously spotted with two or three 

 tints. But if this supposition be valid some other one, on (it Avould 

 seem) a wholly different principle, must be found to explain why 

 perhaps the eggs that are at once the most delicately and most 

 richly coloured laid by any bird are those of the Snow-BuNTiNG, 

 Pledrophanes nivalis, which except in rare instances are so sedu- 

 lously concealed as to be almost beyond the reach of reflected light ; 

 and again, why the several species of Nuthatch, Sitta, which must 

 have been ages in learning the art of masonry they so skilfully 

 practise, lay eggs more deeply dyed than those of their felt-making 

 brethren the Paridx (Titmouse), or their feather-bed cousins the 

 Wrens and the Treecreepers. But the supposition would seem 

 to break down wholly as an explanation of the variable colouring 

 offered by eggs of the Fantail- Warbler, Cisticola cursitans or schoeni- 

 cola — whether the observations of M. Lunel (Bull. Soc. Ornithol. Suisse, 

 1865, pp. 9-30, pi. 7), referring the marvellous differences they 

 present to the season of the year at which they were laid, be correct 

 or not, for the ark-lii^ structure of the nest remains constant. No 

 more can here be added on this matter, interesting as it is, and 

 worthy of much more investigation than it has received.^ 



The grain of the egg-shell offers characters that deserve far 

 more consideration than they have received until the attention of 

 Herr von Nathusius having been directed to the subject by some 



^ Having introduced Hewitsou's name in this connexion, and having pre- 

 sently to refer to him again, I may say at once that his remarks on the color- 

 ation of eggs, and some other subjects, have been frequently repeated, of course 

 with more or less modification and verbose addition, by various plagiarists who 

 have sometimes forgotten to mention the source of their information. With the 

 greatest regard for my old friend, I am bound to say that the principles on which 

 he wrote, more than fifty years since, are such as no man of science can accept 

 now ; but they were those of his time, and the more recent adaptors of them are 

 behind theirs. 



