68 CORALS AND CORAL ISLANDS. 



object. The accompanying figures of the animal are from the 

 drawings made to illustrate a yet unpublished memoir by 

 Prof. Agassiz. They are copied from the " Sea-Side Studies " 

 of Mrs. Agassiz and Alexander Agassiz. In fig. c, the polyps 

 are of the natural size, while fig. a represents one of them en- 

 larged. The polyps, as is observed, stand very prominent 

 above the cells of the corallum, because only the bases of 

 them secrete coral ; and the buds, which open between the 

 calicles, are hence lateral buds; the coral has much resem- 

 blance to that of an Orbicella, in which budding is margin- 



ASTRANGIA DAN^E, AG. 



al. The tentacles have minute warty prominences over 

 them, which are full of lasso-cells, each about a 500th of an 

 inch in length, or about two-thirds larger than those of the 

 white cords that edge the internal septa. The corallum, 

 though massive, is somewhat irregularly lobed above, and 

 grows to a diameter of two or three inches. It is covered 

 with stars an eighth of an inch to a sixth across (fig. £), which 

 are usually crowded together, the intervening wall being very 

 thin and solid. The author alluded to the crowd of stars in 

 the name Pleiadia, which he proposed for the genus in his 

 Report on Zoophytes (p. 722). 



The genus Cladocora, containing slenderly branching ra- 



