102 CARBONIFEROUS PERIOD. 



ous from apex to calyx ; longitudinal stnse crossed b)^ more or less distinct 

 wrinkles, and very fine encircling lines of gi'owth. 



Calyx comjDaratively deep ; its sides rather tliin between the septa, and 

 of nearly nnifomi thickness from I'im to bottom ; rays within the calyces of 

 the largest specimens sometimes reaching, fifty in number, not projecting 

 far inward from the sides except toward and at the bottom, upon which 

 they reach the columella ; bottom of the calj'x really sloping downward 

 from the columella all around, and ending abruptly against the sides, but 

 the numerous septa, by gradually approaching the columella from the sides, 

 give the bottom a concave appearance when viewed from above ; septal 

 fossette not very conspicuous, usually occupying a little more than the 

 space of one principal body-ray, or septum ; sejDta below the calyx, less 

 numerous than the rays within it, well developed, and reaching nearly or 

 quite to the columella, but none of them apparently becoming consolidated 

 with it except the one opposite the septal fossette ; columella strong, trans- 

 verse section broadly oval, projecting considerably from the calyx, bluntly 

 crested, well consolidated by the almost complete fusion of the middle por- 

 tions of the tabulae that comj^ose it, not firmly united to the surrounding 

 portions of the corallum, but readily cleaving from them when the parts are 

 broken ; when thus separated, its sui-face shows somewhat twisted, longi- 

 tudinal, raised, stria; which correspond more or less closely with the inner 

 edges of the septa, but are not really separated parts of them, as they at first 

 sight appear to be ; tabidse comparatively thin, between the columella and 

 the sides, sloping or arching downward, and ending abruptly against the 

 inner side of the outer wall. 



Length of the largest specimen in the collection, along its convex side, 

 upward of four centimeters ; diameter of the calyx, twelve millimeters. 

 The average size of full-grown specimens is not materially less. 



Our examples present a different aspect from typical forms of S. proli- 

 ferum, and they perhaps belong to a different species ; yet it is difficult to 

 point out distinct structural differences of specific value. They have, how- 

 ever, a larger average size, and are more robust, less wi'inkled, and less con- 

 torted than typical forms of S. ]proliferum, which characters seem to indicate 

 at least a distinct variety, for which the name sauridens is proposed. The 



