INTRODUCTION. xv 



formed by processes that appear to arise from the lower part of the inner edge of the 

 septa. Pali in general lobulated at their apex, narrow, tall, and appearing also to proceed 

 from the inferior part of the margin of the septa, their size diminishing as they approach 

 nearer to the columella. Septa nearly equal, very slightly exsert, and closely set, their lateral 

 surface strongly granulated, and presenting sometimes traces of imperfect dissepiments ; 

 four or five cycla ; systems equally developed. Costa nearly equal, straight, closely set, 

 projecting very little, and delicately granulated. 



Typ. sp., Paracyathus procumbens, Milne Edw. and J. Haime, loc. cit., tab. x, fig. 6. 



12. Genus Heterocyathus. 



Milne Edw. and J. Haime, loc. cit., p. 323, 1848. 



Corallum simple, sub-cylindrical, extremely short, and adherent by a basis at least as 

 broad as the calice, but appearing free, because in the adult state it imbeds in its tissue the 

 small shell to which it is fixed. Calice circular, or nearly so, with a broad, deep fossula ; 

 Columella small, and composed of very slender vertical styli. Pali broad, thin, and denti- 

 culate. Septa very exsert, broad, thick, and covered with conical granulations arranged in 

 radiate series ; four or five cycla, the last of which is more developed than the penultimate 

 one, and composed of septa that diverge from the older septa as they advance towards the 

 centre of the visceral chamber. Costa straight, thick, closely set, and strongly granulated. 



Typ. sp., Heterocyathus cequicostatus, Milne Edw. and J. Haime, loc. cit., tab. x, fig. 8. 



13. Genus Deltocyathus. 



Milne Edw. and J. Haime, loc. cit., p. 325, 1848. 



Corallum short, conical, free, and presenting no trace indicating its having been 

 adherent when young. Calice circular, and almost flat. Columella multipartite. Pali highly 

 developed, and very unequal, those of the penultimate circle the largest, and turned towards 

 those of the antepenultimate row, so as to form with them a series of deltse. Septa slightly 

 exsert. Costa straight, unequal, distinct down to the basis of the corallum, and strongly 

 granulated, so as to assume a moniliform appearance. 



Typ. sp., Deltocyathus italicus, Milne Edw. and J. Haime, op. cit., tab. x, fig. 11 ; Stephanophyllia 

 italica, Michelin, Icon. Zoopb., tab. viii, fig. 3. 



14. Genus Tropidocyathus. 



Milne Edw. and J. Haime, loc. cit., p. 326, 1848. 



Corallum simple, free, presenting no trace of former adherence, compressed, and having 

 at its basis a large, thick, transverse, vertical crest, or two projecting lobes, resembling 

 wings, or the fins of sepia. Calice elliptic and arched, its small axis being much higher 

 than its long axis ; fossula not very deep. Columella oblong and multipartite. Pali entire ; 

 those corresponding to the penultimate cyclum of septa taller and broader than the others. 

 Septa exsert ; the six systems equally developed. Costa well marked, especially at the 

 upper part of the wall, and covered with small granulations. 



Typ. sp., Tropidocyathus Lessonii, Milne Edw. and J. Haime, loc. cit. ; Flabellum Lessonii, Michebn, 

 in Guerin's Mag. de Zool., 1843, tab. vi. 



