50 PERCY SLADEN TRUST EXPEDITION 



1. Eghinopora lamellosa (Esper). (PL 8, fig. 6 ; 14, figs. 2 — 6 ; 15, fig. 1 ; 



16, fig. 6.) 



1797. Madrepora lamellosa, Esper, Forts. Pflanz., p. 65, pi. 58, figs. 1 and 2. 



1816. Echinopora rosidaria, Lamarck, Hist. Aniiii. sans vert., ii, p. 253 — 2'* edit., p. 397. 



1830. Echinastrea rosularia, Blainville, Diet. Sci. Nat. Ix, p. 344, pi. 35, fig. 2 — Manuel d'Aotinol., p. 378, 



pi. 56, fig. 2. 



1848. Echinopora undulata, Dana, Expl. exp. Zooph., p. 278, pi. 17, fig. 3. 



1848. Echinopora rosidaria, Dana, Expl. exp. Zooph., p. 279. 



1848. Echinopora rpflexa, Dana, Expl. exp. Zooph., p. 280, pi. 17, fig. 2. 



? 1848. Echitiopora horrida, Dana, Expl. exp. Zooph., p. 282, pi. 17, tig. 4. 



18 . Echinopora rosularia, Milne Edwards, Atlas grande edit. Regne anim. Cuvier, Zooph., pi. 85 ter. 



1850. Echinopora rosularia (pars), Milne Edwards and Haime, Ann. Sci. Nat., ZooL, 3"^ ser., xii, p. 185. 



1857. Echinojjora rosularia (pars), Milne Edwards and Haime, Hist. Nat. Corall., ii, p. 623. 



1864. Echinopora Jlexuosa, Verrill, Bull. Mus. Comp. Zool. Harvard, i, p. 54. 



1877. Echinopora rosularia, Studer, Monat. Ak. Wiss. Berlin, p. 643. 



1877. Echinopora fiexuosa, Studer, Monat. Ak. Wiss. Berlin, p. 643. 



1877. Echinopora striatula, Studer, Monat. Ak. Wiss. Berlin, p. 644, fig. 10a and h. 



1889. Echinopora rosularia, Ortmann, Steinkorall. Siid. Ceylons, Zool. Jalirb., iv, p. 531. 



1904. Echinopora rosularia, Gardiner, Fauna Geogr. Maldives and Laccadives, p. 782, pi. 63, fig. 37. 



Corallum. Very thin, margins irregularly folded up, attached below in the centre. 

 Peritheca dense, with slender spinulate echinulations, their bases usually fused to form low 

 thin perithecal costae, towards edges of corallum spines disappearing but ridges remaining. 

 Corallites almost circular, projecting up to 2 mm. (usually 1'25 mm.), up to 6 mm. apart 

 (average 3 mm.). Calices with diameter 3"5 mm., depth I'Smm. ; quite shallow towards 

 edges of corallum. 



Septa in three orders, tertiaries very thin, up to 4 quatei'naries sometimes present, 

 sides rough, perforated, edges denticulate. Primaries sometimes thicker than secondaries, 

 these and up to 6 tertiaries meeting columella; septa of even thickness along their breadth 

 or somewhat thickened in thecae, margins vertical, exsert to 1 mm. The exsert ends of 

 primaries and secondaries divided by two notches — not extending below calicular 

 margins — into an inner arched lobe and two outer bluntly-pointed teeth, the last appearing 

 as the first costal tooth. Costee comparatively thin, with one or two spinulate echinula- 

 tions. Columella of close ti-abeculse, up to two-thirds width of calyx. 



Polyps. (1) Tertiary couples of mesenteries absent. (2) Directive grooves deep 

 and narrow. (3) Nematocysts I less numerous in ectoderm of oral-disc and outer wall 

 of edge-zone than in E. gemmacea, but fewer in stomodeeal ridges and in straight regions 

 of mesenterial filaments than in E. hirsutissima. (4) Entocoelic pleats in stomodseal 

 region of polyp horizontal, better developed than in E. hirsutissima or E. gemmacea, 

 being thick, unconstricted at their bases, extending over the outer half of primary 

 mesenteries and more or less of uniform size along the entire pleatal region ; mesogleea 

 thickest in pleatal region ; no exocoelic pleats. (5) Mesenterial endoderm of more or less 

 uniform thickness along the entire width of primary mesenteries. (6) Endoderm in outer 

 wall of edge-zone as thick as the ectoderm over it, somewhat thinner in oral-disc. 

 (7) Convolutions of mesenteries abundant towards bases of polyps. 



Remarks. A. Polyps. The polyps are circular in outline, relatively small, the largest 

 one being 4 mm. in height and 2'5 mm. in diameter and invariably directed obliquely 



