[ 303 ] 



VIII. A Bescription of the Madreporaria dredged up during the Expeditions of H.M.S. 

 ' Porcupine ' in 1869 and 1870. By Professor P. Martin Duncan, M.B. (Land.), 

 F.R.S., F.G.S., Professor of Geology to King's College, London, &c. 



Bead May 16th, 1871. 



[Plates XXXIX. to XLIX.] 



CONIENTS. 



I. Introduction, p. 303. III. Descriptions of and Remarks upon the Species, p. 309. 



II. Classification of the Species, p. 306. IV. Tables of Localities, &o., p. 338. 



I. Introduction. 



ZOOPHYTOLOGISTS have long known that some simple Madreporaria, or Stony 

 Corals, live at a depth of from 80 to 150 fathoms on the floor of the Atlantic and 

 Pacific Oceans, in areas remote fi-om coral reefs. The existence of Madreporaria at 

 corresponding depths in the Mediterranean Sea has also been known practically to those 

 interested in the red-coral fisheries. Nevertheless it was until lately tacitly admitted 

 that all corals obeyed the laws which regulate the bathymetrical distribution of reef- 

 building forms. But it is only dui-ing the last four years' that a fime and peculiar^ coral 

 fauna has been proved to exist not only at great depths but also in temperatm-es 

 ranging from below freezing-point to 55° Fahrenheit. Although Foraminifera and 

 Echinodermata have been brought up from profound depths by the sounding-apparatus, 

 no trace of a stony coral had been observed ; and it was not until the United-States 

 Coast Survey dredged between Key West and Havana in 1867, that any proof of 

 the existence of Madreporaria at a great depth was obtained. On May 24th, 1867', 

 stony corals were dredged up alive from the depth of 270 fathoms ; and on May 25th 

 the same species was obtained from 350 fathoms. In the following year, 1868*, many 

 species were di-edged up under the supervision of M. de Pourtales, as naturalist, off the 

 Florida reef, in the course of the Gulf Stream, from 43 to 324 fathoms. 



The expedition of H.M.S. ' Lightning,' in the same year, conducted under the super- 



' The researches of Sars, MacAndre^v, Norman, and J. Gwyn Jeffreys prepared the way for those of tho 

 United States Expeditions and of H.SI.SS. ' Lightning ' and ' Porcupine,' under Fourtales and A. Agassiz, and 

 WyviUe Thomson, Carpenter, and Gwyn Jeffreys respectively. 



• "Coral Faunas of Western Europe," Quart. Journ. Geol. Soc. 1870, P. M. Duncan. 



» "Contributions to the Fauna of the Gulf Stream at great Depths," by L. F. de Pourtales, No. 6 Bulletin 

 of the Harvard Museum of Comparative Zoology, 1st series. 



* Op. cit. 2nd series. 



VOL. VIII. — PARTY. March, ISIS. 2x 



