CORALS AND CORAL-ANIMALS. 173 



sectional title of the Madirpomrin aporosa. Between this group and an equally extensive one 

 which, as the corallum is very distinctly porous, is known as the Madrcporaria perforata, there 

 exists a small tribe in which the septal walls, while themselves imperforate, are united to one 

 another by a multitude of minute calcareous rods, technically termed " synapticulae," which 

 communicate to the coralla a semi-porous consistence. As this intermediate group is most 

 prominently represented by what are known as the Mushroom-corals, genus Fungia, and its 

 allies, it is most usually distinguished by the title of the Fungidae. 



An outline of the general contour and aspect of a living Mushroom-coral has been already briefly 

 given, in association with the descriptive texts of Plates XXIII. and XXIV. of the photographic 

 series. In a typical representative of the genus Fungia, as illustrated by Fungia crassitciitaculata, 

 the subject of Plate XXIII., the corallum is subcircular or ovate, and flattened on its under surface ; 

 on the upper (and usually more or less convex) one, it is traversed by the concentrically radiating 

 septal plates which, when denuded of their investing membrane, bear a marked resemblance to 

 the so-called gills of a mushroom. These Fungiae are what are known as solitary corals, each 

 corallum consisting of a single individual corallite, which, with the investing polyp, closely 

 resembles in its fully-expanded state an ordinary skeletonless sea-anemone, such as the common 

 British Dahlia-anemone, Tcalia crassicoriiis. Of the many species of Mushroom-corals that are to 

 be found upon the Barrier reefs, the one, Fungia crassitentaciilata, figured in the plate above 

 referred to, is undoubtedly the most noteworthy. In the living state, its thick, massive tentacles, 

 when fully extended, project to a length of two or three inches beyond the margin of the 

 corallum, whose presence is completely hidden by the investing membrane and mass of tentacles 

 developed from the oral disk or peristome. In colour, the tentacles of the species range, in 

 different individuals, through every shade of bright apple-, grass-, and olive-green, and again 

 through various shades of light, dark, and golden brown. The extremities of the tentacles 

 among all the varieties are usually white or light grey or yellow, and are more or less 

 distinctly inflated. Radiating striae, generally of a yellow tint, usually mark the course of the 

 principal septa on the investing membrane, and are continued inwards until they join the oral 

 aperture. A characteristic illustration of the aspect of a living, fully-extended example of this 

 species is afforded by Fig. 13 of Chromo plate No. VI., which represents a reproduced 

 print from the original photograph, coloured from life. 



The handsome species of Mushroom-coral now under notice occurs most abundantly in 

 the northern or Torres Strait district of the Great Barrier system, and is sometimes so 

 plentiful in the sheltered lagoons left by the receding tide, that, where the green-tinted 

 variety predominates, they appear to be richly carpeted with a vivid green vegetation. The 

 inflated, fully-extended tentacles, in point of fact, bear a considerable resemblance to a 

 crowded growth of the common green seaweed, Enteromorpha. The adult Mushroom-corals 

 repose freely on the sea-bottom ; but it is interesting to observe that in their early 



