304 BEOFESSOE P. M. DLTsCAN OX THE 



vision of Professor Wyville Thomson, Dr. Carpenter, and Mr. J. Gwj'n Jeffreys, in the 

 North Atlantic, afforded satisfactory evidence of the existence of a coral fauna in the 

 deep sea, and in water of a very different temperature from that usually considered 

 necessary for the Madreporaria ; but it was not until 1869 that, under the same able 

 dii-ection, the systematic dredgings of H.M.S. ' Porcupine ' proved the existence of coral 

 life at a depth of 705 fathoms'. 



A description of this dredging expedition was read before the Royal Society in 1870, 

 by Messrs. Carpenter, Wyville Thomson, and J. Gwyn Jeffreys^, and a report on the 

 corals' obtained by those naturalists, and intrusted to me for examination and descrip- 

 tion, was read before the same Society March 24th, 1870. 



AVhen the second expedition was preparing to start in 1870, under the same able 

 guidance, particular requests were made to me to advise concerning the dredgings, so 

 far as the corals were concerned. The employment of the " hempen tangles," instead 

 of the crushing dredge, had already commended itself to the superintendents of the 

 dredging operations ; and it was a satisfaction to find that by using these simple means 

 a fine collection of specimens was obtained off the west and south-west coast of the 

 Spanish Peninsula and along the Mediterranean coast of Africa, from depths which 

 reached to 1095 fathoms. 



All the information I have required has been freely given me by the three naturalists 

 who were responsible for the dredgings, and also by M. Lindahl their assistant. 



Professor A. Agassiz and Count Pourtales were of great assistance to me by sending 

 me their reports and also a collection of the specimens dredged up by them, so that I 

 have been enabled to compare the North-Atlantic forms with the West-Indian and 

 Floridan types. 



I have also had the advantage of examining the results of the dredgings conducted 

 by Mr. Kent, of the British Museum, and of his assistance in comparing specimens. 



The majority of the specimens dredged up and entangled during the two expeditions 

 of the ' Porcupine ' were alive and in good condition ; a few had been dead for some 

 time and were covered with Sponges, Serpulse, and Polyzoa. Specimens were not 

 invariably obtained at every dredging ; and it is evident that corals live here and there 

 in patches, and that they mostly frequent rocky gi-ound, although some species live in 

 the Globigerine ooze. Fine muddy sediment appears to be unfavourable to coral life ; 

 and many of the dead specimens which came up in the dredge were filled with it. 



It is somewhat remarkable that so many weU-known species, especially of the Medi- 



' Proc. Eoyal Society, 1870. 



' W. B. Carpenter, F.E.S., Wj-riUe Thomson, F.E.S., and J. Gwyn Jefteys, F.E.S., " Deep-Sea Eesearches," 

 Proc. Eoy. Soc. 1870, vol. xviii. pp. 397-492. 



W. B. Carpenter, F.E.S., and J. Gwyn Jeffreys, F.E.S., " Deep-Sea Eesearches," Proe. Eoy. Soc. 1870, 

 vol. xix. pp. 146-221. 



' P. M. Duncan, ' Porcupine '-Expedition Madreporaria, Proc. Eoy. Soc. 1870, vol. xviii. pp. 289-301. 



