928 
THE VOYAGE OF H.M.S. CHALLENGER. 
The sand in which the eggs are hatched does not feel warm to the hand, but rather, 
in the daytime at least, cool, and it is always moist. Several sets of eggs were gathered, 
placed in large vessels full of sand, and taken on board the ship, under the impression 
that it would be easy to succeed in hatching them artificially, and obtain eggs in all 
stages of development. It was found, however, that all the eggs perished within a 
couple of days. No doubt a certain definite amount of moisture' must necessarily be 
maintained in the sand as well as a certain constant temperature in order to keep the 
eggs alive and develop them. The sand, in which the eggs were, was exposed to the 
sun in the daytime and covered up at night. Turtles’ eggs are, however, apparently not 
hatched by the direct daily heating by the sun of the sand in which they are buried ; 
what appears to be the case is, that the eggs are buried at such a depth that the 
sand there maintains a constant mean temperature, never hot and never cold. The 
eggs of a species of Mound Bird ( Megcipodius ) are hatched under closely similar 
conditions in the Philippine Islands (see p. 535). 
The young Turtles fresh from the eggs are kept as pets by the seamen at Ascension in 
buckets of sea water. They eat chopped-up raw meat ravenously, using their fore- 
fins to assist their beak-like jaws in tearing the morsels. Turtle-meat is served out twice 
a week as rations to the inhabitants of Ascension, who are all naval employes. A series 
of embryo Turtles in various stages of development were removed from the eggs and 
carefully preserved, and formed the material, together with a series sent home by Staff- 
Surgeon Maclean of the Challenger, who was stationed on the island in 1877, for 
the excellent Monograph by Professor W. K. Parker on the Development of the Green 
Turtle, which has been published in the Zoological Series of Reports. 1 
A visit was paid in the small steam vessel which is employed in collecting Turtles 
from the various bays of the island to Boatswain Bird Island, a breeding place of various 
sea birds. As the vessel steamed along the shore of the main island large flying Gurnets 
(Dactylopterus) rose, scared by the vessel, and skimmed rapidly away in front of the 
bows. The attempt was made to shoot them on the wing, a novel experiment, but 
quite without success. The flight was rapid and the boat was in constant motion, 
pitching and rolling ; no doubt in calm weather the thing might be done. 
Boatswain Bird Island is a high rock separated from the main island by a narrow 
channel. The sides of the rock are precipitous, but a sailor had managed to climb up 
and fix a rope at the summit, so that it hung down the cliff. The cliff surface was covered 
with guano hanging everywhere upon it in large projecting masses and formations 
resembling stalactites. The party clambered up the -cliff by means of the rope, being half 
blinded and half choked by the guano dust on the way. 
In holes on the sides of the cliff, burrowed in the accumulated guano, nest two kinds of 
Tropic Birds ( Phaethon cethereus and Phaethon Jtavirostris). In bracket-like nests, as at St. 
1 Zool. Chall. Exp., part y., 1880. 
