DEPARTMENT OF MARINE BIOLOGY. 193 



oceans are essential, and the Department of Marine Biology is one of 

 the few existing agencies which is free to conduct such studies. 



The following publications, representing work done wholly or in 

 part under the auspices of the Department of Marine Biology, have 

 appeared during the year: 



Ctjshman, J. A. 1920. Observation on living specimens of Iridia diaphana, a species of 



Foraminifera. Proc. U. S. Nat. Mus., vol. 57, 153-158, pi. 19-21. 

 Harvey, E. N. 1920. The nature of animal light, ix+182 pp., 33 figs. 

 Mayor, A. G. 1920. The effect of diminished oxygen upon the rate of nerve-conduction 



in Cassiopea. Amer. Jour. Physiol., vol. 51, 543-549. 

 . 1920. The reefs of Tutuila, Samoa, in their relation to coral-reef theories. Proc. 



Amer. Phil. Soc, vol. 43, No. 3, 14 pp., 3 figs. 

 Bartsch, Paul. Experiments in the breeding of Cerions. Paper from the Department 



of Marine Biology, vol. xiv, Carnegie Inst. Wash. Pub. No. 282, 56 pp., 59 pi. 

 MoRTENSEN, Th. Studies in the development of Crinoids. Paper from the Department 



of Marine Biology, vol. xvi, Carnegie Inst. Wash. Pub. No. 294, iv+94 pp., 



28 pis., 10 figs. 



REPORTS OF INVESTIGATIONS. 



Studies of Alcyonaria and of Borings through Reefs of Samoa, by Lewis R. Gary. 



The remeasuring of the recorded alcyonarian colonies growing on the reefs 

 at Utelei, Pago Pago Harbor, Tutuila, Samoa, after a period of approximately 

 two years from the time of the last measurements, shows that nearly all of the 

 colonies could be recognized, and that in most instances the increase in size 

 had been proportionately as great as during the first year for which the records 

 were kept. Especially striking was the manner in which the stony corals had 

 been overgrown by the Alcyonaria, so that in many instances the several 

 alcyonarian colonies had come in contact, completely covering the less rapidly 

 growing forms, the hving tissues of which had entirely disintegrated. 



A third boring on the Utelei line, 925 feet from the shore, which was made 

 during the past summer, reached the underlying basalt after having passed 

 through 124 feet of coral. This boring completes the evidence that this reef 

 at least rests upon a substratum which for as much as 350 feet inward from 

 its outer margin has been eroded to a practically level surface at a depth of 

 approximately 20 fathoms below present low- water level. The inner boring, 

 280 feet from shore, where the substratum was reached at a depth of 68 feet, 

 indicates that the planation to the lower level had not at this point extended 

 inward to the present shore-line by somewhat more than the above-mentioned 

 distance. Since, however, the cove at Utelei is situated well within the harbor, 

 with a prominent headland protecting it from the direct effect of the strongest 

 wave-action, it appears not unreasonable to suppose that in more exposed 

 locations, for example at the harbor entrance or on the outer shore of the 

 island, the erosion would have extended nearer to the present shore-line 

 than at Utelei. 



The character of the material brought up in the core-barrel, or in the " calyx- 

 barrel" above the former, showed that the constitution of the reef at the 925- 

 foot boring, which was about 20 feet from the reef-margin, differed in no essen- 

 tial respect from that indicated in the earlier, more shoreward borings. Sand 

 was found abundantly in the upper 50 feet of the reef, with occasional soHd 

 lumps of massive stony coral or alcyonarian spicules; but the framework of the 

 reef was, as usual, made up of branching coral, in the interstices of which 

 the sand occurred in larger or smaller pockets. Throughout the lower por- 



