neiv Genus of Devonian Corals. 521 



The only other point in connexion with this singular crys- 

 talline structure with regard to which a few words may be 

 said is as to whether or not a similar structure is ever deve- 

 loped in R. crinalis as well as in R. stromatoporoides. Con- 

 sidering that these two species are very closely allied and that 

 they commonly occur in association, we should expect that 

 such a purely inorganic change as that which induces the 

 '^ stelh'micans^^ condition would equally affect both these 

 forms. As a matter of fact we think it probable that of the 

 many specimens in the " stellimicans " state which we have 

 examined some are really referable to R. crinalis j Schliit., 

 and not to R. stromatoporoides^ Roem. As, however, the 

 induction of this condition more or less extensively obliterates 

 the normal structures of the coral, we are not prepared to 

 assert this positively. We do meet, however, with " stelli- 

 micans " specimens in which the tubes are decidedly larger 

 than they are in the majority of examples (see PI. XVI I. 

 fig. 1), and it is not improbable that these represent examples 

 of R. crinalis which have undergone this peculiar process of 

 mineralization. We have, moreover, a specimen from the 

 Devonian rocks of Devonshire consisting of two superposed 

 colonies which presumably belong to a single species, and of 

 which one colony is in its normal state, while the other is in 

 the extreme form of the " stellimicans " condition. The un- 

 altered colony (PI. XVII. fig. 6) is undoubtedly i2. crinalis^ and 

 the ^^stellimicans'''' colony (PI. XVII. fig. 5) '\& probably the 

 same, though its tubes are certainly not so large as those of 

 its fellow. * 



Finally, we cannot pass over without remark the singular 

 tubercles which are commonly developed in R. stromatopo- 

 roides at the angles of junction of the corallites (PI. XV^I. 

 figs. 1 a, 3, and 5). These structures are something like the 

 " acanthopores " of the Monticuliporoids, but are undoubtedly 

 of a different nature. They are best seen in specimens in the 

 '^stellimicans''^ condition, when the walls are not completely 

 destroyed ; but there are indications of tlieir presence in even 

 normal examples of the species. We are inclined to think, 

 however, that they are merely the result of mineralization 

 affecting in some peculiar way the thickened angles of junc- 

 tion of the tubes. 



Formation and Locality. Abundant in the Middle Devo- 

 nian of Gerolstein, in the Eifel, where it occurs in all its 

 forms. Rare in the Middle Devonian of Teignmouth, 

 Devonshire. 



Ann. & Mag. N. Hist, Ser. 5. Vol. xvii. 36 



