152 THREE CRUISES OF THE "BLAKE." 



sive distribution in the Atlantic, and is a common Caribbean 

 species. 



One of the most elegant of the West Indian corals is the pure 

 white Amphihelia rostrata (Fig. 473), which must have spread 



Fig. 473. Amphihelia rostrata. * . 



at least twelve centimetres. It has been dredged to a depth of 

 nearly 900 fathoms. Axohelia mirabilis (Fig. 474) is very 

 common in the Caribbean, and is rather variable. Many spe- 

 cimens are deformed by barnacles occupying the end of the 

 branches, which soon become entirely covered by the coral, 

 leaving only a small opening. As representatives of one of 

 the most natural of the families of corals, we may mention 

 Thecopsammia socialis (Fig. 475) and T. tintinndbulum, of 

 which the living polyp is of a handsome pinkish orange color. 



