CELLEPORA COSTAZII. 411 



the avicularium, turned a little towards one side and 

 looking upwards. The aperture is large^ sometimes orbi- 

 cular^ sometimes slightly produced and pointed below, 

 sometimes with a more decided sinus on the lower margin. 

 Many cells occur in which it is simply orbicular. The 

 spatulate avicularia, which are of very large size, in keep- 

 ing with the zooecia, are present in great numbers, and 

 form a striking characteristic. 



The discrimination of forms amongst the Cellejjorce is a 

 very difficult task, and it is necessary to make large allow- 

 ance for the variability of the tribe ; but the present seems 

 to have the characters of a species. 



Cellepora CosTAzii, Audouin. 



Plate LV. figs. 11-14. 



Cellepora Costazii, Audouin, Espl. (1826) : Savigny, Egypte, pi. vii. fig. 4. 



Cellepora bimucuonata, Hass. Ann. N. II. vii. (1841), 367, pi. ix. fig. 1. 



Lepralia Hassallii, Johnston, B. Z. ed. 2 (1847), 304, pi. liv. fig. 3. 



Cellepora Hassallii, Busk, B.M. Oat. ii. 86, pi. cix. figs. 4-6 ; var. a, 

 Quart. Journ. Micr. Sc. (n. s.) tI. 263, pi. xx. fig. 6 : Man- 

 soni, Brjoz. foss. Ital., Contr. iv. 17, pi. iv. fig. 22. 



Celleporina Hassallii, Gray, B.M. Kacl. 128. 



Cellbporaria Hassallii, Smitt, CEfv. K. Vet.-Akad. Forh. 1867, Bihaug, 

 33 & 197, pi. xsviii. fig. 211. 



Zocecia ovate, smooth, irregularly disposed, decumbent in 

 the younger portions of the colony, erect and crowded 

 in the older, sometimes an umbo on the front of the 

 cell, a little below the aperture ; orifice ample, suborbi- 

 cular, with a rounded sinus on the lower margin ; peri- 

 stome raised, an erect tubular process on each side, 

 bearing on its summit a small oval aviciilarium facing 

 towards the aperture, lower lip sometimes mucronate ; 

 large, raised, spatulate avicularia distributed amongst 

 the cells, sometimes wanting. Ocecia recumbent, rounded 

 rather shallow, much broader than high, with an arched 



