SYRINGOPORID^E. 205 



lafa, Van Cleve. The chief distinction between Cannapora and 

 Syringopora would, in fact, seem to consist in the possession 

 by the former of horizontal instead of infundibuliform tabulae. 

 On the other hand, Cannapora, Hall, approaches Favosites in 

 the possession of "mural pores " in those parts of the corallum in 

 which the corallites are in actual contact; and it maybe directly 

 compared with such members of the Favositides as Vermipora, 

 Hall, in which a partially disjunct condition of the tubes exists. 



Chonostegites, E. and H., has been shown (see supra) to be a 

 true member of the Favositidce closely allied to Michelinia, De 

 Kon., and it cannot, therefore, be associated with Syringopora. 



Thecostegites, E. and H., again, is defined as having an in- 

 crusting submassive corallum, composed of short cylindrical 

 corallites, which are united by strong mural expansions in the 

 form of more or less distinct horizontal platforms. The walls 

 of the corallites are well developed, and are only free in the 

 intervals between the periodic expansions just spoken of. The 

 calices are circular ; imperfect septa to the number of twelve 

 are present ; and the tabulse are distinctly horizontal (Pol. Foss. 

 des Terr. Pal., p. 297). The type of this genus is T. Bouchardi, 

 Mich., from the Devonian of Ferques in France; and Milne- 

 Edwards and Haime mention that they have seen specimens 

 from the Falls of the Ohio, and possibly from the Eifel. They 

 further point out that the genus has a decided affinity to Syrin- 

 gopora, and that it has special relations with 5\ tabulata, Van 

 Cleve. They give a short and very insufficient description of 

 a second species (T. auloporoides) from the Devonian of Spain. 

 Recently Dr Rominger (Foss. Cor. of Michigan, p. 83) has 

 made out a strong case in favour of the view that Thecostegites 

 Bouchardi is really nothing more than a peculiar condition of 

 growth of Syringopora tabulata, Van Cleve. Dr Rominger, 

 however, seems to consider that the original specimens of T. 

 Bouchardi were derived from the Falls of the Ohio, which is cer- 

 tainly not the case ; and until these specimens are re-examined, 

 it cannot be said that absolutely final evidence has been brought 

 forward in favour of the complete suppression of Thecostegites. 



