24 Jt. G. CarruthevH — A Revhion of some Carboniferous Corals. 



A diagram, Fig. 1, is appended as a key to the terminology used in 

 this paper. In this connection the work of Kunth is followed, with two 

 exceptions. The first, not of any importance for our present purpose, 

 is the recognition of two more primary septa (the counter-lateral 

 septa) in addition to the four enumerated by the German author. 

 The second point concerns us more nearly. Previously most figures 

 of the calyx and of cross- sections of rugose corals were so arranged 

 that the cardinal fossula, if it occurred on the convex side of curvature 

 of the coral, was shown on the upper side of the figure ; if, on the 

 other hand, the cardinal fossula occurred on the concave side of the 

 coral, it was shown on the lower side of the figure. In the 

 illustrations accompanying the present paper the cardinal 

 fossula is in all cases shown on the upper side of the figure, 

 since it is believed that recent work ' enables us to extend to rugose 

 corals the orientation adopted by common consent for other Antliozoa. 



The terms ' major' and ' minor' septa are here used instead of the 

 commoner terms ' primary ' and ' secondary.' Since only the first six 

 septa to be developed can properly be regarded as primary, the small 

 intermediate septa should, if the common nomenclature be retained, 

 be called tertiary septa, as has indeed been sometimes done. To avoid 

 any confusion, it seems better to adopt some non-committal terms for 

 the long septa and their intermediates, and therefore the terms 

 'major ' and ' minor' septa are here used. 



Genus ZAPHRENTIS, Eafinesque & Clifford. 



Corallum simple, turbinate, conical or cylindro-conical, usually 

 more or less curved. Major sefta well developed, reaching quite, 

 or very nearly, to the centre of tlie corallum. 31vior septa may or may 

 not be present; they are usually short. No columella is developed. 



The conspicuous cardinal fossula is variable in position, and is com- 

 pletely enclosed and surrounded by septa, which fold round and form its 

 walls. The tabula, though variable in character, are always a prominent 

 feature, and are in direct connection with the wall ; convex vesicles 

 may arise on their upper surfaces, especially towards the circumference 

 of the corallum ; but these never assume a vertical alignment, and 

 consequently in no case is there any trace of an external dissepimental 

 zone of the nature of that found in Campophyllum and similar genera. 



The above definition of the genus Zaplirentis is largely taken from 

 that given by Messrs. Nicholson & Thomson (Ann. & Mag. Nat. Hist., 

 ser. IV, vol. xvi, 1875, p. 426). In that article the nature of the 

 cardinal fossula is for the first time regarded as "a character of 

 primary importance in the definition of the genus." A restriction of 

 this kind is necessary if the genus is not to attain imwieldy pro- 

 portions, and although the above definition does not pretend to be 

 founded on the specimens from which the original diagnosis was 

 prepared, it undoubtedly represents the genus as understood at the 

 present time. I have been unable to gather from the original de- 

 scription of MM. Rafinesque and Clifi'ord any clear idea as to the 

 nature of their specimens, and for the present, therefore, have retained 

 the conventional definition in common use. 



1 Ann. & Mag. Nat. Hist., ser. vii, vol. xviii (1906), p. 362. 



