PRELIMINARY REPORT. 95 
lee side is made up of large islands, and on the weather-side of shallow 
flats separated by narrow gaps, allowing but a comparatively small amount 
of water to be driven into the lagoon from that side. In a semi-closed 
lagoon like Pinaki there are but few corals, when compared to those 
found in such an open lagoon as Wotje, and there are none growing in 
the closed lagoon of Niau. 
The fact remains that the corals growing on the sea face of an atoll or 
of a barrier or fringing reef are far more massive and abundant than those 
which grow inside of the lagoon. While it cannot be denied that the 
corals of the lagoon are in many localities more numerous in species, 
yet they never extend to as great a depth, and never have the luxu- 
riant growth or form the colossal heads which characterize those of the 
sea face. 
Furthermore, the amount of animal life, irrespective of corals, which 
finds its sustenance on the sea face of a reef is very great, and its super- 
abundance does not seem to indicate a lack of food-supply as compared 
with that existing in the lagoon. 
To be of value it seems to me that these quantitative experiments 
should be accompanied with a comparative statement of the amount of 
water sifted through each lagoon, as it were, in which the experiments 
are conducted. And furthermore, the amount of animal life coming to 
the surface, or living to a depth of ten or fifteen fathoms outside of any 
atoll, must be fully as fluctuating a quantity in these regions as it is 
known to be elsewhere, depending upon the season, the time of the day, 
and atmospheric conditions, all of which are still unknown factors to us, 
not only in the Pacific, but even at localities where observations on the 
relative abundance of surface organisms, and the causes which influence 
it, have been carried on for many years. 
The record of the observations of the surface temperatures and of the 
specific gravities of the sea were in charge of Dr. H. F. Moore. Of 
course, until the record has been carefully computed, we can compare it 
only in a very general way with the results obtained in the Pacific by 
the “ Challenger” as tabulated by Dr. Buchanan,’ and specially with Plate 5 
1 Physics of the “ Challenger” Expedition, Vol. I., London, 1884. 
