556 ME. E. E. L. DIXON AND DK. A. VATTGHAN ON [Nov. 191 1, 



The D 23 mutation : — The tabulae are gently depressed and close- 

 set ; the fossular depression starts near the margin. Hence, 

 in a horizontal section, the contours of the tabulae, between 

 the septa and in the fossular valley, are close-set and 

 nearly parallel. 



The thin vesicular wrapping is developed early, and is 

 practically continuous over the whole of the cylindrical 

 portion. 



The y species ( = Ganinia cornucopia 3 , Mich., emend. Carruthers) 

 PI. XL, fig. 4 : — The tabulae are well spaced, and the 

 fossular depression starts near the centre. Hence, in a 

 horizontal section, the contours of the tabulae, between the 

 septa and in the fossula, are few and widely spaced. 



The thiii vesicular wrapping is developed late and, even 

 in the adult, is seldom present over the greater part of the 

 cylindrical portion. 



Occurrence in the South- Western Province. — The y 

 species is doubtless common at most localities at the top of Z 2 

 and in C x , although Burrington (Mendips) and Stackpole Quay 

 (Pembroke) are the only localities which have as yet been 

 thoroughly searched. 



At the top of D 2 and in D 23 the upper mutation is usually to be 

 found, and is often abundant. It is almost invariably cylindrical 

 for the greater part of its length, and broader than the ' cornu- 

 bovis' variant from the Upper Tournaisian (specimens indistin- 

 guishable, externally, from that variant are, however, occasionally 

 found). 



In Gower, this mutation occurs in D 2 of Port Eynon and 

 throughout D 2 _ 3 of North Colts Hill Quarry and of Oystermouth 

 Quarry. 



In the Bristol area it is a very rare fossil in D 2 . In the west of 

 the South- Western Province — Horizon e of Eagwen Point near Pen- 

 dine — specimens are common, and at Bullslaughter Bay, near Boshes- 

 ton (South Pembrokeshire), it is very abundant in D 2 in association 

 with Glyphioceras sphericum (Martin) and a small Cyathaxonia. 



Caninia (?) sp. (PI. XL, fig. 5.) 



This coral is remarkable for the extent and slope of the tabulae, 

 for the shortness of the septa, and the practical absence of a fossula. 

 The tabulae are flat, and extend almost completely across the 

 corallum ; they slope very steeply downwards from the convex to 

 the concave side. 



Owing to their high dip, a cross-section cuts several tabulae ; and 

 consequently the interseptal spaces, on the concave side, appear to 

 be vesicular. 



Above a tabula the septa are very short and amplexoid without 

 any septal break ; underneath a tabula, they are elongated on the 

 concave side and short on the convex side with a small fossular gap. 

 Minor septa are only developed in the calyx. 



