﻿272 DE. A. VAUGHAN ON IHE PALiEONXOLOGlCAL [May 1905, 



while the fossula is less marked and is occupied by a prominent 

 primary septum. 



The tabulae are domes, with only one strong groove which forms 

 the fossula. 



Discussion. — The species, as described and figured by Edwards 

 & Haime, differs from our specimens in having (1) a short, broad- • 

 angled form ; and (2) an oval calyx. It agrees, however, in all 

 the essential characters of septal grouping and tabular flexure. 



Evolution and mutation. — From the characters of very 

 young specimens, it is most probable that Zaphrentis aff. cornucopia: 

 was derived from an ancestor closely allied to Z. aff. Phillipsi ; on the 

 other hand, the radial symmetry of the septa and the flexure of 

 the tabulae indicate early Oaninia-like characters. These sugges- 

 tions are in agreement with the time-range of Zaphrentis aff. 

 cornucopia? ; it makes its first appearance in Z , after Z. aff. Phillipsi 

 was well established, and reaches its maximum at the top of Z 2 , 

 where Caninia begins to appear ; it dies out in the lower part of 

 the Syringothyris-ZonG. 



Caninia, Michelin ; emended, M'Coy, ' Brit. Palseoz. Eoss.' p. 28. 



— Zaphrentis cylinclrica and allies, Edwards & Haime, ' Monogr. Brit. 



Foss. Cor.' pt. iii, p. 171. 

 ■ = Campopthyllum, Thomson (non Edwards & Haime), Proc. Phil. Soe. 



Glasgow, vol. xiv (1883) p. 375. 

 = Caninia, Vaughan, Proc. Bristol Nat. Soc. n. s. vol. x (1903) p. 102. 



This genus resembles Zaphrentis in the well-developed fossula 

 and the consequent axial symmetry. It differs from Zaphrentis in : 



(1) The predominance of the tabulate over the septate structure. 



(2) The insignificance of the outer wall and its replacement by a thick 



shell of vesicles. 



The genus Caninia was originally founded by Michelin to cover 

 all corals having deep fossular depressions, the type being C.gigantea 

 (in which were included both the Devonian and the Carboniferous 

 forms). M'Coy restricted the genus to its type-species, and re- 

 defined it by the vesicular character of the wall. 



The differences of this genus from Campophyllum, Edwards & 

 Haime, and from the Carboniferous Cyathophylla will be noticed 

 later (p. 276). These differences have already been discussed in 

 Proc. Bristol Nat. Soc. n. s. vol. x (1903) pp. 102-103. 



Caninia cylindrica (Scouler). 



Siphon ophy Ilia cylindrical, Scouler, in M'Coy, ' Syn. Carb. Limest. Foss. of 



Ireland' p. 187 & pi. xxvii, fig. 5. 

 Zaphrentis cylindrica, Edwards & Haime, ' Polypiers Foss. Paleoz.' p. 339. 

 Caninia gig ant ea, M'Coy, 'Brit. Palaeoz. Foss.' p. 89. 

 Zaphrentis cylindrica, Edwards & Haime, ' Monogr. Brit. Foss. Cor/ 



pt. iii, p. 171 & pi. xxxv, figs. 1-1 b. 

 (?) Campophyllum Murchisoni, C. cylindricum, C. giganteum, Thomson, 



Proc. Phil. Soc. Glasgow, vol. xiv (1883) pp. 376, 377, 378 & pi. vii, 



figs. 4, 9, 11. 



