FAMILIES AHfD GENERA OP THE MADKEPORAEIA. 107 



G-enus Solenaste^a, Milne-Edwards Sf Jules Haime, Hist. Nat. 

 des Gorall. vol. ii. p. 495 (1857), altered. 



Colony massive but light, convex above, incrusting or tall, often 

 gibbous, rarely plane. Corallites long or sbort, united by a well- 

 developed exotheca, which extends beyond the small costse. 

 Calicos with free margins, which are usually circular, but some- 

 times unsymmetrical in outline. Columella spongy or feebly 

 developed. Septa thin or stout, imperforate, dentate. Endotheca 

 fairly developed. Gremmation extracalicinal. 



Distribution. — Fossil. Eocene : Europe, Borneo. Oligocene : 

 England. Miocene : Europe and West Indies. Crag : Eng- 

 land (?). — Suhfossil. Eed Sea. — Becent. Eed Sea, Indian Ocean, 

 Singapore, Caribbean Sea. 



Subgenus Ctphaste^a, (genus) Milne-Edwards Sf Jules Uaime, 

 Hist. Nat. des Corall. vol. ii. p. 484 (1857). 

 The generic characters are as in Solenastrcea, but the septa are 

 cribriform. 



All so-called Solenastrseans with cribriform septa must enter 

 this subgenus, and all the recorded species of the genus, according 

 to Milne-Edwards and Jules Haime. 



Bistrihution. — Fossil. Miocene : West Indies. — Becent. Red 

 Sea, Caribbean Sea, Pacific, Australian seas. 



Genus Plesiaste^a, Milne-Edivards Sf Jules Haime, Hist. Nat. 

 des Corall. vol. ii. p. 489, pi. D 7. fig. 5 (1857). 



Colony variable in shape, massive, convex or subplane above, 

 with a naked and costulate common wall. The corallites may 

 have thick or thin walls, be close or distant, and in the first 

 instance may fuse inferiorly, and in the last may have a feeble 

 exotheca between them. Calices shallow, circular and free. Colu- 

 mella spongy. Septa well developed, exsert, denticulate near the 

 calicular edge. Pali well developed and in contact with all the 

 septa which precede those of the last cycle. Endotheca very 

 feebly developed. Costse and exotheca usually well developed. 

 Epitheca absent. Gremmation occurs in the intercalicinal areas. 



Bistrihution. — Fossil. Eocene : India (Siad). Miocene : 

 Europe, Sind, Asia. — Becent. Pacific, North- Australian seas, 

 Indian Ocean, Caribbean Sea. 



In the Tertiary deposits of San Domingo are several species of 

 Flesiastr(jea-\ookmg corals (Duncan, "West-Indian Corals," Proc. 

 Geol. Soc, Nov. 1863, p. 37 et seq. and pis. iv. & v.). There are 



