On the ' Porcupine ^- Expedition Maclreporaiia. 289 



the varieties of shapes (some of wliich had been deemed of specific 

 vahie) which I had observed in tlic separate assemblages of specimens 

 from the Mediterranean, the 8icihan tertiarics, and the British and 

 Scottish seas. 



A perfect series of specimens from all these localities can be so 

 arranged as to show a gradual structural transition from form to 

 form ; so that the most diversely shaped CaryophylVue can be linked 

 together by intermediate shapes. The CanjophylUa clavus and 

 CaryopliyUia cyathus can be united by intermediate forms, and all of 

 these to Caryophyllia Smiihii and Caryophyllia borealis. 



It is impossible to dctei'mine which is the oldest form ; but they all 

 appear to be reproduced by variation on some part of the area 

 tenanted by the section of the genus. The variability of the Caryo- 

 j)hyllue of the Sicilian tertiary deposits is very marked ; and it is 

 equally so in the groups which live on disconnected spots in our 

 waters. The Dingle-Eay series presents the greatest amount of 

 variabilitj', and indeed is most instructive ; for by applying the 

 range of it to the classification of such genera as Trochocyathus and 

 Montlivaltia a great absorption of species must ensue. 



The Dingle-Bay Caryophyllue are evidently the descendants of 

 those Avhich lived in the Western and Southern-European seas 

 before those great terrestrial elevations took place which were con- 

 nected with the corresponding subsidence of the circurapolar land 

 and the subsequent emigration of Arctic mollusca. They are not 

 closely allied to the recent West-Indian species ; but they occupy a 

 position in the Coral-fauna representative of them. The same re- 

 mark holds good with reference to the affinities of the recent and the 

 cretaceous CaryophyUke. They are not closely allied, and they 

 belong to different sections of the genus ; but they hold the same 

 positions in the economy of the old and new distribution of animal 

 life, and the recent forms arc representative of the older. The 

 examination of the Dingle-Bay Caryophyllia} tends to prove that a 

 species is really the sum of the variations of a series of forms. 



A specimen was dredged up in 705 fathoms, temp. 42°-G5 F., and 

 it exactly resembles forms which are frequently found in 90 fathoms, 

 and at a temperature slightly below that of the surface. M. Al- 

 phonse Milne-Edwards obtained some CaryophyUke from the cable 

 between Corsica and Algiers in 1110-1550 fathoms. The bathy- 

 metrical range of these forms is therefore very great. I have placed 

 the species borealis in the first place, and regard the old species C. 

 clavus, C. Smithli, and C. cyathus as varieties of it. 



Ceratocyathus ornatns, Seguenza. — A beautiful specimen of this 

 rare form was dredged up from a depth of 705 fathoms with some 

 Caryophyllia} and a small Isis. The species is hitherto unknown 

 except in the Sicilian miocene*. 



Flahellum laciniatum, Ed. & H.— This is the Ulocyathus arcticvs 

 of the late Prof. Sars. Many specimens were dredged xip; but most 



* Seguenza, " Disquisiz. Palennt. int. ai Corall. Foss.," Mem. della 

 Ileale Accad. dell. Sci. Torino, serio ii. tomo xxi. 1804. 



