418 PROCEEDINGS OF THE ACADEMY OF 



to terminate in the porous substance of the corallum, between the cells, with- 

 out directly connecting them. 



This small group of corals appears to be more nearly related to Cyathoceris, 

 of Edwards and Haime, than to any other genus, either recent or fossil, with 

 which we are acquainted. It differs, however, in having the outer walls per- 

 forated, and in being destitute of distinct rays, as well as in the peculiar 

 wedge-like form of the base of the corallum, which is also usually, if not 

 always, free instead of attached. We regard the first of the following species 

 as the type of the genus. 



Sphenopoterium obtcsum. Corallum short,abruptcuneiform,wider than high; 

 base carinate, nearly straight, or very slightly sinuous in the middle ; sides 

 expanding rapidly upwards from the keel. Cells from four to about nine, 

 compai'atively large, generally rather deep, conical, and where not more than 

 four or five, rounded, and separated by thick interstices, but becoming angular, 

 with thin intervening partitions, where more crowded. Surface stria? fine, 

 and showing a tendency to converge towards the middle of the base, often 

 anastomosing, so as to form a kind of shagreen-like style of ornament. 



Length or height of a large specimens with nine cells, inch ; breadth, 



inch ; thickness, inch; diameter of one of the cells, 0-29 inch. 



Locality and position. 



Sphenopoterium compressum. Corallum compressed,wider than high, carinate 

 on each lateral margin, and apparently retaining a scar of attachment at the 

 middle of the base ; sides sulcate betweeen the cells, widening rapidly upwards 

 on the edges, and very gradually on the sides. Cells three or more, com- 

 paratively large, rather deep, rounded, with thin walls ; arranged in a row 

 parallel to the longer transverse diameter of the corallum. Surface finely 

 shagreened by the anastomosing of the striae. 



Length or height, 0-57 inch ; breadth, 0-93 inch ; thickness, 0-35 inch ; 

 diameter of cells, 0-26 inch. 



It is possible this may be a variety of the preceding species, though its com- 

 pressed form, thinner walls, and lateral carina?., give it quite a different aspect. 



Locality and position. Same as last. 



Sphenopoterium enorme. Corallum small, subglobose, obtusely subturbi- 

 nate ; rounded, and apparently retaining some remains of a scar of attach- 

 ment at the base. Cells four or more, rather irregularly disposed, circular, 

 and moderately deep. Surface slightly more coarsely marked than the last, 

 but otherwise similar. 



Height, 0-45 inch ; transverse diameter about 0-43 inch ; breadth of cells, 

 about 0-18 inch. 



Locality and position. Rockford, Indiana, from beds probably of upper De- 

 vonian age, but containing Carboniferous Goniatites. 



Sphenopoterium cuneatum. Corallum compressed, cuneate, longer than wide, 

 base sharp, a little rounded on the lateral edges. Cells from two or three, to 

 five or six, rather deep, arranged alternately on each lateral edge, and directed 

 obliquely outward and upward ; rounded or somewhat oval at the aperture, and 

 more or less compressed towards the base ; sometimes having one or two 

 slightly prominent ridges extending part of the way up the sides ; punctae of 

 the walls numerous and distinct. Surface striae fine, closely arranged, rather 

 regular, and minutely crenulate, directed obliquely inward and downward 

 from the cells, and passing more or less nearly parallel to each other to the 

 base, on the lower flattened half. 



Length, 0-75 inch; breadth, 0-43 inch; thickness, 0-21 inch; diameter of 

 cells, about 0-15 inch. 



Ljocality and position. Spurgen Hill, la. From beds generally considered on 



parallel with the Warsaw Limestone. 



[Oct. 



