694 Reports on the Zoological Collections made in Torres Straits j 1888—1889. 



the canals in the mesenteries, which are extremely well marked, are distinctly 

 connected with the spaces in the body-wall. Large yellowish nematocysts are 

 present in the outer ectoderm, in many of the lacunse of the mesogloea, and in the 

 mesenteric canals, being especially numerous in the latter. A very few zooxan- 

 thellse are also present. Besides the lacunse, numerous isolated cells are enclosed 

 in the mesogloea, many of them being drawn out into the fine protoplasmic threads 

 found in other species of Zoanthese. The endoderm is granular, of uniform 

 thickness, and contains occasional zooxanthellse. The usual diffuse muscular 

 layer is present. 



Sphincter muscle. — Tlie single mesogloeal sphincter muscle is well developed. 



Disc and tentacles. — The ectoderm is thick, and in the tentacles the ectodermal 

 muscular layer is well developed, the mesogloeal folds being complicated and 

 branching. The mesogloea also forms a thick layer and often contains cell 

 enclosures. The endoderm is very thin. 



(Esophagus. — The ectoderm of the oesophagus was not well preserved in our 

 specimens, so that it was not possible to determine its nature or arrangement in a 

 normal condition. There is a well marked groove, and the mesogloea, which 

 elsewhere is thin, becomes much thickened in this region. 



Ilesenteries. — The mesenteries present the usual microcnemic arrangement. The 

 imperfect mesenteries are usually well developed. The ectoderm of the oesophagus 

 appears to be reflected in the usual manner, but owing to its bad preservation it is 

 not possible to determine the exact nature of its arrangement. The mesoglcea is well 

 developed, and in each mesentery it contains one or more sinuses or canals which 

 extend throughout the entire height of the mesentery. These sinuses contain 

 numbers of large nematocysts, similar to those found in the ectoderm of the body- 

 wall. The muscles of the mesenteries are not strongly developed. They form 

 almost simple layers. 



Gonads. — The sexes are distinct ; we found female, but no male gonads, in 

 several of the polyps which we examined. They were all taken from the same 

 colony. 



Palythoa kocliii, n. sp. 

 (PI. Lxi., fig. 12; PI. Lxm., fig. 9.) 



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

 coenenchyme incrusting, of moderate thickness. Polyps so crowded us to usually 

 have a polygonal contour. The whole surface is incrusted witli calcareous particles, 

 etc. Twenty capitular ridges and furrows. Tentacles, 40. Mouth large. 



Colour. — Colour of colony, finely speckled buff and cream, each polyp demar- 

 cated by a pale border ; tentacles similar, but translucent. Disc thin, translucent, 



