GEOLOGY AND PALEONTOLOGY OF THE CANAL ZONE. 



355 



ASTEROSMILIA HILLI, new species. 



Plate 80, figs. 4, 5, 6, 6a. 

 1899. Asterosmilia species Vaughan, Mus. Comp. Zool. Bull., vol. 34, p. 149. 



I find it difficult to explain why a species so common as this one 

 could have so long remained undescribed. There are from Bowden, 

 Jamaica, 41 specimens in the Henderson and Simpson collection, 20 in 

 the Hill collection, and 9 in the T. H. Aldrich collection, making 

 a total of 70 specimens that, I have studied from this one locality. 

 A series of ten of the best specimens of the Henderson and Simpson 

 collection have been selected as the co types. 



Corallum cornute with a pointed base and attached, at least in its 

 early stages, rather slender, curved in the plane of the greater trans- 

 verse axis of the calice. The following table gives the measurements 

 and number of septa in the type specimens. 



Dimensions of and number of septa in Asterosmilia hilli. 



Specimen No. 



Greater 

 diameter 

 of calice. 



Lesser 

 diameter 

 of calice. 



Height of 

 corallum. 



Number of septa. 



1 



2 



3 



4 



5 



6 



mm. 

 4 

 4 

 4 



4.5 

 6.5 

 7 

 6 

 9 



9.5 

 i 10 



mm. 

 3 



3.75 

 3.5 

 4 



5.5 

 6 

 5 

 7 



8.75 

 19 



mm. 

 6.5 

 7 

 9 



10.5 

 12 

 15 

 15.5 

 18.5 

 19 

 25 



About 24, and probably some rudimentary. 



24, and a few rudimentary. 



24, and a few rudimentary. 



24+17 of the fourth cycle. 



24+20 of the fourth cycle. 



24+20 of the fourth cycle. 



8 



24+20 of the fourth cycle. 



9 





10 



48, four complete cycles. 



i About. 



The calice is oblique, its upper edge being considerably higher than 

 its lower. In the measurements given above the height of the coral- 

 lum is measured from the tip of the pedicel to the highest point of the 

 calicular margin. 



The wall is only moderately thick, externally there is a variable 

 amount of pellicular coating. Costae corresponding to all septa, 

 distinct, but usually not prominent. There is a fair amount of varia- 

 tion in the costal characters. In some specimens the costae of all 

 cycles are equal or subequal, low, flattish or only slightly crested; 

 in others, those corresponding to the septa of the first and second 

 cycles of septa are decidedly more prominent than the intervening 

 costae. Those corresponding to the third cycle of septa may be 

 slightly more prominent than those corresponding to the fourth. 

 Sometimes costae of both kinds are combined in one specimen. 

 Rather often in an intercostal space there is a raised thread or line 

 which does not correspond to a septum. Minute, crowded granula- 

 tions are scattered over the surfaces of the costae and in the inter- 

 costal spaces. 



