7. Anthozoa (incl. Hydrocorallia). A. Zoantharia. 13 



Studeri 2 ) points out that while in the Central Pacific the Madrepores 

 and the majority of the Astrseidse reach their northern limit in the Sandwich 

 Islands, in the western part the Madrepores extend much further north. They 

 are found along with Euphyttia , Plesiastrcea , Galaxea , Pavonia, Diaseris and 

 Pocillopora in the Liu-Kiu and the Bonin Islands and one species of Madre- 

 pora is recorded from Kagoshirna Bay in Kiu-Siu (31 N. lat.). These northern 

 forms are less luxuriant than those from tropical coral reefs. By means of 

 currents the warm equatorial water is carried northwards and the temperature 

 of the sea around the Liu-Kiu, Kiu-Siu and Bonin Islands falls below 20 

 only in January or February. These currents cause larvae from the reefs of 

 Formosa and the Philippines to be carried northwards where they may still 

 settle down in water of a suitable temperature. This is a condition similar 

 to that whereby the Gulf Stream in the Atlantic Ocean renders possible the 

 formation of the reefs of the Bermudas. The resemblances between the coral 

 faunas of the Panama region and of Hawaii are best explained by reference 

 to feeble currents which sweep from the west on to the coast of California 

 and Mexico. The author describes new corals (Halomitra 2 n., subgenus Podo- 

 bacia 1 n., Montipora 2 n., Porites 4 n.). See also Marenzeiier. 



Gardiner( 1 ) states that the Maldive group is made up of a large series of 

 comparatively shallow banks which are covered with coral reefs rising to 

 the surface. Some banks have on their circumference the single ring-shaped 

 reefs of perfect atolls while others are studded with small isolated reefs many 

 of which are of circular form with shallow lagoons (atollons) which are every- 

 where coming into free communication with the lagoons of the atolls. The 

 two classes of bank merge into one another, and the changes going on at the 

 present day are such that the atolls may have arisen by the fusion of the 

 smaller reefs. All land in the group owes its origin directly or indirectly to 

 elevation and in most atolls is very markedly washing away. The changes 

 going on are not consistent with the view that the reefs were formed on sub- 

 sidence of the land. 



Gardiner( 2 ) gives an interim report of his work on the coral reefs of the 

 Laccadives, Maldives and Ceylon. In May 1899 the rocky shore near Ben- 

 tota (Ceylon) was covered with small coral colonies which had evidently grown 

 during the previous north-east monsoon. In September these had been washed 

 away in the south-west monsoon. At Galle and other two stations numerous 

 recently-living colonies of corals , particularly of Porites and Pocillopora of 

 4-8 months' growth were found completely silted up with sand, etc. A notice- 

 able point about the reefs immediately round Ceylon is the comparative ab- 

 sence of reef-building Nullipores. From surveys of Minikoi (an isolated atoll, 

 the most southern of the Laccadive group) it was clear that there had been 

 an elevation of the original reefs to at least 25 feet above low-tide level. Evi- 

 dently the boring organisms, which attack dead corals, especially in the lagoon, 

 and cause a larger surface to be exposed, render the solution of the coral 

 more rapid, resulting in the decay of the dead coral which consequently cannot 

 form points of attachment from which fresh reef growths may arise. The 

 lagoons of atolls are generally formed by solution of the central rock of ori- 

 ginally more or less flat reefs. 



Werth behandelt die Entstehung des Rifffelsens und die Bedingungen der' 

 Ansiedelung von Korallenstocken, indem er speciell auf die Riffe der ostafri- 

 canischen Kftste eingeht. Die Korallen fassen FuB in einem weichen kreidi- 

 gen Kalkstein, der wohl aus den Triimmern von Molluskenschalen, Korallen 

 etc. durch partielle Lo'sung in dem warmen Seewasser und Verdunstung bei 



c* 



