Haddon and Shackleton — Actinice : I. Zoanthece. 695 



the dark interval cavity shining through ; very iinely dotted with brown and 

 opaque white, ffisophagus gray, furrowed. Capitular ridges whiter than the rest 

 of the polyp. 



Dimensions. — Diameter of polyps about 5 mm. 



Locality. — Fringing reefs, Thursday Island, and Mabuiag. 



This species is named in honour of our distinguished Gei'man colleague, who 

 was the first to discover the precise arrangement of the mesenteries in the 

 Zoantheee. 



Body-wall (PI. lxiii., fig. 9). — As in the last species the body-wall and 

 coen en chyme may be regarded as one. The ectoderm, where present, is continuous, 

 and is covered by a thin cuticle. Incrustations, consisting of spicules and grains 

 of sand (the latter being for the most part less coarse than those found in P. hoiuesii), 

 form a dense border at the union of the ectoderm with the mesogloea. They are 

 scattered more sparingly through the deeper parts of the mesogloea. Lacunar, 

 canals, and cell islets are found throughout the mesogloea. Nematocysts are present 

 in both the ectoderm and the lacunae. Zooxanthellse are also found in the ectoderm 

 and lacunae, as well as in the endoderm. The endodermal muscle is well developed. 

 The endoderm forms a uniformly thin layer. 



Sphincter muscle. — The mesogloeal sphincter is long and well developed. 



Disc and tentacles. — The structure of the disc and tentacles is very similar to 

 that found in P. hoivesii. 



(Esophagus — The ectoderm of the oesophagus is not well preserved, but it appears 

 to be thrown into well marked folds. There is a very slight groove, and no 

 appreciable thickening of the mesogloea in this region. 



Mesenteries. — The mesenteries are arranged as in other Brachycneminse. The 

 imperfect mesenteries are well developed. The reflected ectoderm is not well 

 preserved, but is evidently arranged in the ordinary manner. Sinuses, similar to 

 those found in P. hoivesii, are found in the mesenteries of this species also. The 

 muscular layers are very simple, there being apparently no mesogloeal plaitings. 



Gonads. — We found male gonads in several of our specimens, but no female 

 organs were present. 



Palythoa ccesia(?), Dana. 

 (PL Lxi., fig. 14.) 



Palythoa ccesia : 



Dana, 1846, Zoophytes, U. S. Exploring Expedition, p. 40. pi. xxx., figs. 3, 3a. Milne 

 Edwards, 1857, Hist. Nat. Coralliaires, i., p. 305. Andres, 1884, Le Attinie, p. 332. 



Form. — Polyps slightly projecting above the surface of the coenenchyme when 

 contracted. Coenenchyme incrusting in small, ovoid, concavo-convex masses of 



