503 



LONSDALE ON MIOCENE CORALS FROM N. AMERICA. 



9. Cellepora quadrangularis. (Sp. n.) 



Incrusting ; cells disposed in concentric layers around numerous centres, no 

 regularity respecting position of distal extremity ; form quadrangular, bounded 

 by a depressed line, surface very slightly convex, minutely foraminated ; mouth 

 not uniformly in same plane with exterior of cell, round, large, margin in gene- 

 ral not raised or thickened, sometimes notched on the proximal edge ; occasion- 

 ally on one side of the mouth a large pyriform opening to a gemmuliferous (?) 

 chamber ; walls of cells not separable mechanically ; vertical fracture concentri- 

 cally laminated ; connecting foramina near the base of the walls numerous. 



This coral agreed with the two pre- 

 ceding in the general Eschara-like cha- 

 racters of the cells, in the variable 

 position of the distal extremity, in exhi- 

 biting no changes or external thicken- 

 ings dependent upon age, and in the 

 situation of the supposed gemmuliferous 

 vesicle or chamber; but it differed in 

 the walls not being separable mechani- 

 cally, fractured surfaces displaying al- 

 most constantly the interior of cells 

 arranged in concentric layers, and not 

 irregular columns detachable singly : 

 also in the oral aperture having a less 

 uniformly persistent position with re- 

 spect to the surface plane of the cell, 

 being in some instances terminal, and 

 it resembled in its general characters 

 much more nearly those of the mouth 

 of Cellepora pumicosa. 



This fossil attained considerable 

 dimensions, one botryoidal mass being 

 4^- inches in width, and 3 in height ; 

 and with the exception of the small 

 Balani around which it was encrusted, 



a. Cellepora quadrangularis : 

 portion of an outer layer 

 magnified, to exhibit the irre- 

 gular arrangement of the cells 

 as respects the oral termina- 

 tion ; also near the asterisk 

 two rows of immature cells. 



b. Greatly enlarged cells, to 

 show more fully the porous 

 structure of the surface, and 

 the characters of the oral aper- 

 tures with the adjacent cham- 

 ber ; the figure includes also a 

 mouthless cell. 



c. A small section, natural 

 size, to represent generally 

 the concentric layers of cells. 



and a central cavity, it consisted of 

 concentric polype- strata enveloping the botryoidal centres. The 

 individual layers had, however, a limited range. The cells, when 

 unaffected by irregularities of surface, had a nearly quadrangular 

 outline ; and the mouth was in the centre of the distal extremity, 

 if unaccompanied by the gemmuliferous (?) vesicle ; but if that 

 structure occurred, it was situated on one side. Many mouthless 

 cells were noticed, both with and without the vesicle ; but the 

 irregularity of development which prevented the formation of the 

 oral aperture, did not apparently interfere in any manner with 

 the perfect conformation of the opening to the supposed repro- 

 ductive chamber. Indications of the progressive mode of con- 

 structing the cells were not observed ; nor, as already stated, were 

 there any signs, either on the surface or subjacent layers, of 

 marked changes or thickenings attendant upon age. In some 

 cases the mouths had apparently been contracted or filled up, but 



