FAMILIES ATTD GENERA OF THE MADEEPOEAEIA. 161 



IV. Alliance AGARICIOTDA. 

 Colonial Loplioseridse, foliaceous or massive, or incrusting. Calices 

 distinct or indistinct, in series separated by coUines. Septo-costae confluent 

 and extending over the collines. 



Genus Agaricia, Lamarck. 

 Genus Pl.esioseris, Duncan. 

 Genus Pachyseris, Ed. & H. 

 Genus Comosekis, d'Orb. 



Subgenus Oroseris, Ed. & H. 

 Genus Hydnophorabacia, d'Achiardi. 

 Genus Coscinar^a, Ed. & H. 

 The genus Oroseris becomes a subgenus. 



Genus AaAmciA, Lamarck, Sysf. des Anim. sans Verteb. (1801) ; 

 Mllne-Udwards ^ Jules Haime, Sist. Nat. des Corall. vol. iii. 

 ' p. 80 (1860). 



Syn. Undaria, Dana. 



Colony foliaceous and irregular in shape. Calices on one or 

 both, surfaces, circumscribed or limited at least on two sides, in 

 transverse or concentric series, which are separated by unequal 

 ridges (collines), over which the confluent septo-costae pass. 

 Columella tuberculous, papillose, or compressed. Septa con- 

 fluent, not numerous. Common plateau striated and naked. 

 Synapticula exist. 



Distribution. — Fossil. Miocene of Sind, Asia ; Europe. — Sub- 

 fossil. Eed Sea. — Recent. Caribbean Sea, Indian Ocean, Eed Sea. 



Genus Plesioseris, Dimcan, Journ. Linn. Sac, Zoology, 

 vol. xvii. p. 309 (1883). 



Syn. Mceandroseris, B-ousseau (pars). 



Colony massive, adherent, and without epitheca. Surface 

 irregular and nodular. Calices in short series, confluent by their 

 septo-costae and with distinct centres. Septa often uniting, solid, 

 except near axial space, where they are trabeculate with ascending 

 processes; granular on the sides, warty and spinulose on the 

 free edges. Columella well developed and papillary. Synap- 

 ticula of two kinds : — 1, long, broad, and vertical, in two rows 

 near the true calicular wall ; 2, small and nodular, near the 

 axial space. Eminences between the series of calices covered bj 

 septo-costae, and having a true wall. Growth by gemmation 

 beyond and between the calices. 



Listribution. — Recent. Pacific. 



LINN. JOITKN. — ZOOLOGY, YOL. XVIIf. 11 



