classed by naturalists among the true Corals, and to which the 

 name "Coralline" is still given. Externally they are hard ; and 

 their substance is so permeated with carbonate of lime that they 

 are as brittle as rigid, and when thrown into any mineral acid 

 will strongly effervesce. After the effervescence has ceased, and 

 the lime been all dissolved, there remains an Algoid body, of the 

 same form as the "Coralline," but soft, and soon dissolving into 

 a mass of small cellules, arranged in slender filaments. The in- 

 ternal substance or living body of the Coralline therefore is an 

 Alga, of similar structure to many others ; and these supposed 

 anomalous productions naturally fall in among the Rhodosperms. 

 The genus Amjpliiroa contains many species, of different ex- 

 ternal habits, several of which are natives of Australia, and some 

 of the more characteristic will be figured in future numbers. 

 The present is one of the handsomest of the subgenus ''Eury- 

 tion," characterized by the flattened, oblong joints, and dichoto- 

 mous branching. It and another aUied form are among the 

 ornaments of the Rottnest reef-pools, where their brilliant reds 

 and purple contrast well with the rich green of the soft-fronded 

 Caulerp(B. 



Fig. 1. Amphieoa australis, — the natural size. 2. Young articulations, — 

 moderately magnified. 



