304 SUMMARY OF CURREI^T RESEARCHES RELATING TO 



(25 p c), Acropora (18 p.c), and Pocillopora (10 p.c). For the first 

 370 feet out from the shore there are no corals 



In the calm waters of the middle zone of the reef flat, 1100 feet 

 from the shore, the most successful genus is '^^^'«{^f '"«' J^/fj 

 dommates over the others. Yet this coral cannot live withm_500 feet 

 of the shore, because of the high temperature nor sy^''^'ein places 

 more than 1650 feet from the shore, because the breakers destroy its 

 fragile stems. Temperature is the dominant factor, even more 

 mportant than silt in determining the habitat of corals. It is probable 

 that the high temperature causes asphyxiation. 'The corals of this 

 Australian ?eef, which are never subjected to cold, can neverthele s 

 withstand low temperature quite as readily as c^u he corals of the 

 'cold devastated' reefs of Florida ; and conversely the Flonda coials 

 can withstand high temperatures quite as well as do those of Australia. 

 In other words, corals are, physiologically speaking of similar con- 

 stitution whether in the Atlantic or the Pacific ; and natural selection 

 ha apparently not operated to improve their cold-withstand.ng or 

 heat-resisting Vwers. The reef building forms must live in water 

 which is warmer than 15' and cooler than :>8 L. _ 



All snecics of reef corals survive without apparent injury aii 

 immersioi for four to five hours in sea water diluted with an equal 

 volume of rain water, and many species can withstand eleven honis ot 

 this treatment. The injurious effects of toirential rams upon coral 

 reefs is due solely to the silt which they cause to be washed outward 

 over the flats. 



Alcyonarians and a Stylaster from West Coast of North America.* 

 S J. Hickson describes from the region of Puget Sound and north of it 

 rh Stulaster norvegicm, Paragorgia arborea, and Pnmnoamlleyi sp. n. 

 • liich are representatives of a circnmpolar fauna ; ^) f --; ^^^ 

 Lm (which is a representative of south-coast fauna) ; and i^^^^^f'^f 

 moresUi sp n., and GaUqorgia fraseri sp.n., which, along with the pie- 

 Xusly desci4ed sea-pen, Osteocella «^i^^f''^'''^f«^'"^' ^^^ /^P^^, „^ 

 common Pacific element which extends both north and south of the Ime 

 between the two sub-regions. 



Protozoa. 



British Fresh-water Rhizopods.t-O.HWailes has continued,, 

 with the assistance of J. Hopkinson, the work ^li^^'^.tl^^,, f «, ^^^f^ 

 Cash left unfinished. The third volume deals with the families 

 Euglyphina, Gromiina, and Amphistomma. 



Observations on Kerona polyporum.J-H. Victor-Jones observed 

 individuals of this ciliated Infusorian wandermg over ^^/^m «^^/-^c?^s 

 (which had fifteen tentacles) both externally and m the food-canal. 



» Proc. Zool. Soc. London, 1915, pp. 541-57 g pi. and ^ fig^;^;,^. , ^ ,.915) xxiv 

 t The British Fresh-water Bhizopoda and Hehzoa. Ray Society {iyi&} xxiv. 



and 156 pp. (pis. 33-57, figs. 111-59). 



X Zoologist, xix. (1915) pp. 186-9 (1 fig.). 



