194 Mr. R. Etherido-e on Chastetes tumidus. 



XXVIII. — Ohservations on Chsetetes tumidus, Phillips. 

 By R. Etheeidge, Jun., F.G.S. 



[Plate XI. figs. 1-3.] 



Ch^tetes tumidus was first described by Prof. Phillips in 

 1836 under the name of Calamojpora tumida* ', but although 

 several figures were given, a very limited description was 

 appended. As Favosites tumida both Portlockf and M'Coy:j: 

 noticed this coral and gave short descriptions of it. It 

 was also recorded under the same name in the early edition 

 of Morris's ' Catalogue' §. In his great work the 'British 

 Palaeozoic Fossils' M'Coy added to and more clearly defined 

 the characters of this coral as Stenopora tumida \\ ; he there 

 notices the characters of the tubes or calices, the nature of the 

 diaphragms or tabulse, and indicates the presence of a con- 

 cave diaphragm nearly closing each of the tubular openings. 

 Messrs. Milne-Edwards and Haime appear to have been the 

 first to refer the Calamopora tumida of Phillips to the genus 

 Chcetetes ^, Although they do not mention the existence of 

 tabulae in their description, yet such appear to be plainly in- 

 dicated in figure 3a, plate xlv., of their 'British Fossil Corals.' 

 Lastly Prof. De Koninck, in a recently issued work **, has 

 given an interesting recapitulation of the principal points in 

 the structure and history of this species, under the name of 

 Monticulipora turn ida. 



The majority of specimens obtained from Scotch carbonife- 

 rous beds, in some of which the species is very plentiful, have 

 the margins of the calices apparently more thickened than is 

 generally represented, although this character is variable even 

 on the same specimen. The calices are in places very un- 

 equally developed, giving rise to spaces every here and there 

 more or less free from openings, or where the latter are much 

 smaller than the generality of those on the same specimen, 

 thus forming spots which to the naked eye appear like plain 

 patches (PI. XI. fig. 1, «). The smaller tubes are about one 

 fourth the size of the larger. On the base of attachment of 

 Chcetetes tumidus the tube-openings are often of a more irregular 

 form than on the branches, becoming oval, and the walls not 



« Geol. Yorksh. vol. ii. t. 1. f. 49-57. 

 t Geol. Eeport, 1843, p. 326, pi. xxii. f. 4. 

 X Svnop. Garb. Foss. Ireland, 1844, p. 193. 

 § Cat. Brit. Foss. 1843, p. 37. || p. 82. 



II 'Polyp. Foss. Terr. Pal. 1851, p. 270 ; also Monog. Brit. Foss. Corals, 

 1852 13 159 



**'Nouv. Rech. Anim. Foss. Terr. Garb. 1872, pt. i. pp. 143-146. 



