438 PROCEEDINGS OF THE GEOLOGICAL SOCIETY, [June 7, 



The following are species with the fourth cycle incomplete : — 



Caryo-phyllia, cylindracea'^ , Eeuss, sp. Wiltshire, Kent, Norfolk, 



Chalk, upper beds usually. 

 Nehon (Manehe). 

 Bilin and Weiss Kerchlitz. 

 „ Lonsdalei, Duncan Dunstable. 



The progress of research, especially in the investigations concern- 

 ing the fauna of the deep sea, has shown that there are some re- 

 markable exceptions to this rather hasty generalization. 



Pourtales described CaryopJiyllia formosa, Pourt., in the ' Contri- 

 butions to the Fauna of the Gulf-stream at Great Depths,' No. 6 

 (Bull, of the Museum of Comp. Zoology, Cambridge, U.S. 1868). 

 This form was dredged up off Havana in 270 fathoms. It has four 

 complete cycles in six systems. Although 1 have not seen the spe- 

 cimen, stUl I can but recognize, from the very able description, the 

 decided fossil facies, if such a term may be tolerated, of the species. 



During the last expedition of H.M.S. ' Porcupine ' f, under the 

 direction of Dr. Carpenter, P.E.S., and Mr. J. Gwyn Jeffreys, F.E.S., 

 many specimens of Caryopliyllice belonging to several species were 

 dredged up, some of which presented the perfect and others the im- 

 perfect development of the fourth cycle. Some species to which 

 they could be referred had hitherto been recognized as extinct forms : 

 and others were new to science. Thus Garyophyllia arcuata, Ed. 

 & H., a well-known Pliocene form, was found not to be an uncommon 

 inhabitant of the deep sea; and Garyophyllia ahyssorum, Duncan, 

 a new species, was discovered in a dredging from the depth of 1095 

 fathoms off the coast of Portugal. 



The falsity of the generalization which would restrict the Caryo- 

 pliyllice with four cycles to extinct forms having been proved, it be- 

 came necessary to compare the forms dredged up from great depths, 

 and which had only four complete or incomplete cycles of septa, with 

 the fossil forms possessing similar arrangements. 



I was especially led to do this on account of my having detected 

 some instances of remarkable persistence of form during some late 

 examinations of large series of corals from different formations. 



Whilst I was impressed with the great variability of the reef- 

 building species of corals, and had obtained proofs of their increase of 

 variation under alterations in the surrounding physical conditions, I 

 became aware of the very persistent character and less variable 

 nature of the corals of the deep-sea fauna. 



During the examination of the corals dredged up from the 

 Channel slope in 690 fathoms (No. 9 dredging, see Messrs. Carpen- 



* Duchassaing (Anim. Ead. des Antilles, p. 15) described a species with an 

 irregular septal arrangement, but which is associated by MM. Milne-Edwards 

 and Jules Haime with the Caryofhyllim having the incomplete fourth cycle ; 

 but an examination of the plate (Hist. Nat. des Corall. plate D 1, fig. 1) proves 

 that there are four complete cycles and part of a fifth, or else that the specimen 

 is a monstrous form having seven systems. For a corresponding monstrosity 

 see P. M. Duncan, Ann. & Mag. Nat. Hist. 1865, vol. xv. p. 276, ph xi. fig. 2, e. 



t My description of the stony corals dredged up in the expedition of H.M.S. 

 ' Porcupine ' is about to be published by the Zoological Society. 



