NOTES AND QUERIES. 337 
growth” in the caves of North Borneo (‘ Zoologist,’ 1885, p. 43) that led 
Mr. Pryer to consider that he had found the source of the material of 
which the nests are made, a supposed discovery which led to the re- 
opening of the controversy (‘ Nature,’ vol. xxx., p. 271). This low plant- 
substance was determined by Mr. George Murray to be the result of the 
growth of a microscopic alga, a species, probably new, of Gleocapsa (Proc. 
Zool. Soc., 1884, p. 532; ‘ Zoologist,’ 1885, p. 147). In the Solomon 
Islands I was only able to obtain the edible nest in one locality (Oima 
Atoll), since the bird usually frequents inaccessible sea-caves and cliffs. 
The nests were of inferior quality, and were for the most part composed of 
fibrous materials derived from the vegetable drift (the husks of pandauus 
seeds especially). The gelatinous substance thickly incrusted the interior 
of the nests and attached them to the rock. The surface of a cliff in the 
vicinity of the cave frequented by the swifts was coated by a reddish gum- 
like growth, which proved on examination to be an aggregation of the cells 
of a protophytic alga about 1-2500 of an inch in size. Unfortunately, my 
specimens of this growth have miscarried, but I feel assured that it is very 
similar to that observed by Mr. Pryer in the Borneo caves, samples of 
which, through the kindness of Mr. George Murray, I had the opportunity 
of seeing at the British Museum. A similar growth is commonly to be 
found coating the coral limestone cliffs in this group. It may be seeu in 
all stages, the older portions being dark-coloured and rather tough, and the 
fresher portions being, as Mr. Pryer aptly remarked, like half-melted gum 
tragacanth. There are but few cells in the fresh alga, the mass being 
apparently composed of cellular débris, immersed in a rather diffluent 
material, the whole somewhat resembling the third section given in Mr. 
Green’s paper (‘ Nature,’ 1886, p. 81). That the salivary glands are 
especially concerned in the production of the gelatinous nest-substance 
there can now be but little doubt, and the investigations of Mr. Green 
have established the nature of its composition; yet it is possible, and I 
make the suggestion with great diffidence, that a vegetable mucin, or a 
substance closely allied to this animal product, may be found in these low 
plant-growths.—H. B. Guppy (95, Albert Street, N.W.) 
Habits of the Emu as observed in Confinement.—The breeding 
habits of the Emu are thus described in a letter to ‘ Nature’ from Mr. 
Alfred W. Bennett, who had an opportunity of watching the habits of this 
bird, which was, during several seasons, successfully bred by his father in 
Surrey. The hen bird, says Mr. Bennett, begius to lay about the end of 
October or beginning of November, and as each brood consists of twenty 
eggs or more, laid at intervals of two days, the process takes about six 
weeks. Before it is completed the cock bird begins to sit. The eggs laid 
subsequently are deposited by the hen by the side of her mate, who puts 
out his foot and draws them under him. As soon as the eggs begin to 
ZOOLOGIST.— auGusT, 1886. 2c 
