CORALS AND CORAL MAKERS. 25 



giving greater firmness to the whole. An example is shown 

 in the figure on i)age 22. In such a case, there is no skin or 

 animal tissue over the outside of the corallum, excepting at 

 its upper extremity, above this calcareous coating. 



Another form of a corallum. the secretion of a single polyp, 

 is illustrated in the following figure of a species of the Fungia 

 family, so-called in allusion to a resemblance to the mushroom. 

 The long mouth occupied a considerable part of the longi- 

 tudinal central line. From the line at the centre, there is the 

 same radiated arrangement of calcareous septa as in the 

 preceding species, though the animal difi"ers greatly in its 



LNACTIS ECHINATA. 



extreme shortness in proportion to the breadth. The corals 

 of this group are also peculiar in having the radiated upper 

 surface flat, or nearly so, instead of concave. The figure is a 

 fourth the natural size. These corals, of the genus Fungia, 

 often exceed a foot in length ; and thus coral animals are 

 sometimes as large as the largest of Actiniae. 



Another species of this genus, the Fungia lacera, V. (for- 

 merly Fimgia echinata^ D., from the Feejees), is represented as 

 it appears when living (excepting a part left off to suit the 

 page) in the following figure. The coral in the perfect state 

 of the animal is wholly concealed, though often showing the 

 points of the teeth of the septa in consequence of the skin 

 being broken. 



