194 SYNOPSIS OF THE CHARACTERS OF THE 



This irregular coral is not uncommon in some districts, but the characters are seldom well seen in a lime- 

 stone specimen, unless accidentally weathered. 



Stromatopoea subtilis. M'Coy. (PL XXVII. fig. 9)- 



Sp_ Ch. — Heteromorphous, composed of thin, concentric layers, pierced by fine, perpendicular tubes ; struc- 

 ture scarcely visible to the naked eye. 



In structure it resembles the S. concentrica, but is much finer and more delicate in all its parts. From 

 the appearance of some of the specimens, a doubt might be entertained of its being organic. 



Ceriopora. Gold. 



Gen. Ch. — Polypidom, tuberose, composed of numerous, thin, concentric layers ; pores round, unequally 

 placed. 



This genus was intended by Goldfuss to include several fossil forms, now referred to Alveolites, Chrysaora, 

 Sec. ; the above definition is of the genus as now restricted. 



Ceriopora distans. M'Coi/. (PI. XXVII. fig. 13). 



Sp. Ch. — Subcylindrical, verrucose ; pores small, equal, conspicuous. 



A coral, which closely resembles the C. verrucosa of the Silurian rocks. The specimen figured is in 

 the collection of the Geological Society of Dublin ; it is more lengthened than usual. Length of specimen 

 one inch five lines; diameter nine lines. 



Verticillopora. De Fran. 



Gen. Ch. — Polypidom, branched, cylindrical, composed of aggregated, polygonal tubes, divided by trans- 

 verse septa ; axes hollow or filled. 



Verticillopora abnormis. Lonsd. ( ?) 



Verticillopora abnormis. Lons.SiA. Syst. (?) 

 Specimens agreeing with the above in general character occur, but too imperfect to furnish a detailed de- 

 scription ; they difltr from the V. duhia, M'Coy, in the greater size and regularity of the ostiolse, the reference 

 is, however, made with much doubt. 



Verticillopora dubia. M'Coy. (PL XXVII. fig. 12). 



Sp. Ch. — Dichotomous, cylindrical, branches obtuse; axis hollow in adults, filled in young branches ; com- 

 posed of numerous, very unequal, polygonal tubes ; ostiolse forming an irregular network on the surface. 



In this species the tubes are very irregular in size and shape, they are parallel to the axis for the greater part 

 of their length, and then diverge towards tlie surface, where they form a very irregular net work ; the hollow 

 space of the axis is very large in proportion to the soHd external part, e.xcept in the young branches, which 

 are completely filled with the tubes. I have not seen the septa. 



Flustra. 



Gen. Ch. — Foliaceous, or incrusting, flexible; cells contiguous, arranged in regular series, forming a reticu- 

 lated surface. 



Flustra palmata. M'Coy. (PL XXVI. fig. 14). 

 Sp. Ch. — Foliaceous, divided into numerous, flattened, palmated branches; cells on both sides, with very 

 numerous, minute, polygonal openings ; their outer covering and opening unknown. 



