Netv Species of Cellepora. 41 



The original laminae are formed by the growth of two single 

 layers of zooecia, back to back ; these eventually being in most 

 instances overgrown with fresh layers of zooecia until, as in 

 the largest specimen, the thickness is very great. In some of 

 the specimens a new layer of zooecia can be seen extending it- 

 self over the surface 'of the older zooecia, and the front walls 

 of these older zooecia have become highly calcified, so as to 

 cause the zooecia to appear to be immersed in the substance of 

 the zoarium and to be almost indistinguishable from one 

 another. In the new layers the zooecia are quite distinct ; Plate 

 IX. Fig 1 shows some zooecia on the growing edge. 



One of the specimens has died of old age, or disease, f(jr the 

 various laminae, which are very thick, have become split down 

 their centres, the bases of the primary layers of zooecia having 

 separated from one another, and the zoarium is in separate 

 segments, which can be fitted together to show the original 

 form. 



The ooecia (PI. IX. Fig. 2) are very remarkable, owing to the 

 presence in the front wall of an upright, elongated, ellijjtical 

 area, with a membranous or chitinous covering, which does not 

 aj)pear to be of the nature of an operculum, as there is no trace 

 of any hinge ; it has come away slightly at the edges in some 

 instances, but that is probably owing to shrinkage in drying. 

 This structure, together with the peculiar zoarial form, is prob- 

 aljly sufficient to warrant a new genus being established for its 

 reception. However, at present I tentatively place it in Celle- 

 jiora. 



EXPLANATION OF PLATES VII.-IX. 



Platk VIL 

 Cellepora verticalis (massive zoarium). .', nat. size. 



Plate VIII. 

 Cellepora verticalis (multilaminate zoarium). ^ nat size. 



Plate IX. 

 Fig. 1. — Cellepora verticalis (zooecia at growing edge), x 48. 

 ,, 2. — Cellepora verticalis (ooecia and older zooecia). x 48. 



