NATURAL SCIENCES OP PHILADELPHIA. Ill 



rapidly enlarging, inseparable, with only occasional and rudimentary dia- 

 phragms, and no radial lamellae. Walls marked internally by vertical striae, 

 and a few pores which communicate between the cells. Exterior, where ex- 

 posed, covered by an epitheca, marked only by irregular encircling striae. 

 Cells increasing laterally and interstitially. 



This genus, perhaps, approaches nearest to Sphenopoterium, Meek and Wor- 

 then. It differs in the absence of the cuneate form of the base even in Sphen- 

 opoterium the cell mouths in this genus being turned indifferently in all 

 directions. The cells also are smaller and more numerous ; and the fewer 

 mural pores communicate from cell to cell, instead of terminating in the in- 

 tercellular substance. But one species has thus far been observed. 



Conopoterium EFFPS0M n. sp. Corallum small, spheroidal, consisting of 20 

 to 50 cells, which are crowded, subcircular or irregularly angulated in trans- 

 verse section, feebly striated internally, and having a thick, feebly wrinkled 

 epitheca. Specimens presenting cells of all sizes. Some tendency is manifest 

 toward a proliferous growth ; some of the lateral cells becoming adherent by 

 their sides to a foreign body. 



Diameter of largest mass, "58 ; diameter of mouth of largest cells, about 

 20. 



From the Lithographic Limestone, Clarksville, Mo., " White Collection " 

 of the University of Michigan. 



ZAPHRENTIS, Rafmesque et Clifford. 



Zaphrentis Ida n. sp. Coral simple, of medium dimensions, in the general 

 form of an inverted cone, strongly curved, with numerous encircling wrinkles 

 of growth, and an occasional deep constriction. Epitheca rather thick, 

 though the vertical lamellae show faintly on the exterior. Cup very oblique, 

 turned toward the shorter side, with a distinct fossette -reaching from the 

 centre to the shorter side. Radial lamellae 31 in a specimen -62 inch in dia- 

 meter. On the side opposite the fossette is a thick lamella reaching from the 

 periphery to the centre ; one-sixth of the circumference on each side of this 

 is another lamella reaching to the centre, and at the same interval from these 

 are two others ; in the fossette, near the periphery, is the rudiment of a sixth. 

 The remaining lamellae do not extend to the centre but become confluent in 

 each sextant, with the principal lamella which lies between them and the fos- 

 sette the fossette taking the place of a principal lamella. There are thus, in 

 each sextant, four subordinate lamellae joining their primaries, except that in 

 one of the sextants adjacent to the fossette there appears a supernumery lam- 

 ella, caused apparently by the splitting of the shortest subordinate or the one 

 next the fossette. Taking no account of this anomaly, the whole number of 

 lamellae is 30, a multiple of six instead of four. 



The spaces between the lamellae are intersected by thin trans verse dia- 

 phragms arranged at unequal distances,, and either flat or concave upwards. 

 There is no correspondence in the positions of the diaphragms in contiguous 

 interlamellar spaces ; and the wrinkles of the epitheca sustain no relation to 

 them, since they are not continuous, but are intercepted by vertical interlam- 

 illar walls ; and besides, they nearly disappear in the peripheral region of the 

 internal cavity. 



Collected by A. Winchell, in the Goniatite Limestone at Rockford, Indiana. 



The septal system of this coral is described above as senary instead of 

 quaternary. The senary arrangement, as a fact, is sufficiently apparent ; and 

 yet it must probably be regarded as illusory the primary lamellae being four 

 instead of six, and the illusion being produced by the mode of confluence of 

 the lamellae of the second and third cycles. 



Zaphrentis acutus ? White and Whitfield. 



Occurs in the Lithographic Limestone of Clarksville, Missouri. "White 

 Collection" of the University of Michigan 



1865.] 



