SIDERASTR.EA. 81 



Siderastrsea galaxea M.-Euw. & II. 



J^Tadrcpora galaxea Ell. & Sol. 



]\Iadrepora astro ites Esper. PI. 35. 



Siderina galaxen Dana (includes two species, probably). 



Slderaslrea galaxea M.-Edw. & H. Ann. Sc. Nat., 3" Se'r., t. XII., 1850. 



Aslrcea radians M.-Edw. & H. Hist. Nat. des Corall., 185 7. 



Of the two species, S. galaxea and siderea, it is douljtful which one 

 Pallas had in view when describing his Madrepora radians. Ellis and 

 Solander have left no doubt about the species, both by the figure and 

 description, which distinctly point to three cycles of septa only ; their 

 specific name ought therefore to be retained. (There are probably still 

 two species confounded under the same name, one of them being from 

 the East Indies.) 



This species forms generally smaller masses than the next, frequently 

 ball-shaped and free. In altitude it ranges higher than any other coral 

 of the Floridian fauna, as small masses are found flourishing in pools 

 left by the tide ; I have even seen small clusters left partially dry in 

 a hot sun, keeping up a communication with the water only by the few 

 lowest polyps of the group. From their position they must have fre- 

 quently been thus exposed, without inconvenience. According to Pro- 

 fessor Agassiz, the polyp has bilobed short tentacles, at different dis- 

 tances from the centre. 



Siderastrsea siderea Blainv. 



Madrepora siderea f Ellis & Sol. PI. 49, fig. 2. 



Astrea siderea Lamk. 



Pavonla siderea Daxa. 



Slderaslra;a siderea M.-Edw. & H. Ann. Sci. Nat., 1849. 



Astrcea siderea M.-Edw. & H. Hist. Nat. Coral., 1857. 



•j 



All the authors previous to Milne-Edwards and Haime appear to 

 have simply repeated Ellis and Solander's description, which is very 

 vague ; the figure accompanying it has very little resemblance to the 

 coral to which we are in the habit of applying the name, so that I 

 think it is very probable that some other coral was meant. 



It is very common on or about the reef, and forms sometimes con- 

 siderable masses. 



NO. IV. ^^ 



