134 



PROF. P. MABTIN DTJNCAN's REVISION OF THE 



numerous synapticula; but in the upper parts there are only 

 numerous sharp-pointed wart-sliaped granules on the sides of tlie 

 lamellae. 



Distribution. — Fossil. Jurassic: Europe. 



Group-Genus Siderastr^ea, Blainv. 



Grenus Siderastr^a (pars), Blainville, Diet, des Sci. Nat. t. Ix. 

 (1830) ; Milne-Edwards Jules Haime, Gompt. Mend, de 

 VAcad. des Sci. t. xxvii. p. 445 (1848) ; amended after 

 Pourtales. 

 Syn. AstrcBa, Ed. & H. (1857). 



Colony massive, convex or plane, dense, incrusting, Corallites 

 united by thin and often indistinct walls. Calicos subpolygonal, 

 deep, margins rounded. Columella small, papillary, made up of 

 asceading trabeculse, which often fuse, here and there, into amass. 

 Septa solid, rather close, thin, denticulate where free, often 

 uniting. Two rows of synapticula close to the wall unite the 

 opposed septal lamellae, and tend to fill up the interseptal loculi 

 near the wall. Se]3ta imperforate. Endothecal dissepiments few. 

 Gremmation submarginal. 



Distribution. — Fossil. Eocene : Europe, Asia. Miocene : Eu- 

 rope, West Indies. — Subfossil. Eed Sea. — Recent. Ked Sea, Indian 

 Ocean, islands olF West coast of Africa, Caribbean Sea. 



L. Agassiz states tbat the soft parts of Siderastrcea are those 

 of the Eungida and not those of tbe Astrseidse, and the tentacles 

 drawn by Pourtales prove this. 



Group-Genus Polyar^a. 



G-enus Poltar^a, K. v. FritscJi, " Foss. Korall. der Nummulit. 

 V. Borneo,'^ Palceonto^rapJiica, Supp. Band iii. (1878). 



Colony massive, with projecting calicos. Corallites free above, 

 united by wall and costse below. Septa numerous, arched, 

 uniting, perforate. Columella spongy and well developed. Dis- 

 sepiments vesicular. Synapticula present. Epitheca well deve- 

 loped, uniting approximated corallites, wrinkled and striated. 

 Gemmation lateral and basilar. Colony increases circum- 

 ferentially. 



Distribution. — Fossil. Eocene : Borneo. 



K. V. Eritsch states that the colony has the habit of Br achy- 

 pTiyllia, Eeuss. 



