34 TALJiONTOLOGY. 



inches; brefidtli of the hxryest corallites, about 0.40 inch; but the average size 

 not more than one-half to two-thirds as much. 



At a first glance, this coral recalls such forms as Cyathophylliim quadri- 

 gemmatiim, Goldfuss, as represented by figs. 6 h and 6 c, plate xviii, of 

 his Petref. Genn. A moment's comparison, however, shows that it is very dis- 

 tinct. In the fii'st place, its corallites are more compactly crowded together, 

 and more strongly radiating, in consequence of the more rapid growth of inter- 

 mediate young corallites, thus leaving no space for any of them to grow 

 out free from the others. In a few instances, where a young corallite grew 

 more rapidly than the others, it became free, and assumed a round or oval 

 outline ; but this foiTu seems never to have been continued for more than 

 very short distance before the rapid expansion of the young brought them 

 into contact laterally, when they assumed angular outKnes like the old ones, 

 thus covered and hidden from view. The form of the calices in the species 

 under consideration, is also quite different, being very shallow or nearly 

 flat for about half-way in from the walls, and then dropping in almost ver- 

 tically ; while, in C. quadrigemmatum, they slope abruptly inward from the 

 walls. The latter likewise has about forty-six nearly equal septa to each 

 corallite. 



It is probably more nearly allied to C. Sedgwicki, Edwards and Hainie 

 (see British Foss. Corals, pi. lii, figs. 3, 3 a), but it difi'ers in having con- 

 stantly a smaller number of septa, which are all thicker at their outer ends, 

 and taper inward, instead of being all thinner there, with the longer sei'ies 

 becoming thickened about half-way in, and then tJiinning inward. 



The young corallites growing up within the old often give the coral the 

 appearance of an Acervularia ; but a moment's examination shows that these 

 inner circles are young corallites, and not inner walls. 



The specific name is given in honor of Dr. E. Palmer, who discovered 

 and brought in the only specimens I have ever seen. They are all silicified, 

 so as to prevent the possibility of ascertaining the internal structure by sec- 

 tions of the corallites. 



Locality and position. — Rio Verde, Arizona; from its aCTinitics, it is 

 believed to be of Devonian a<je. 



