NATURAL SCIENCES OF PHILADELPHIA. 253 



furrows at the angles distinct and linear ; sides without a mesial furrow, 

 (fostae exceedingly fine and closely arranged, arching gently towards the aper- 

 ture, and sometimes interrupted or alternating at the middle ; most distant at 

 about 0*80 inch from the apex, where there are 10 or 11 in the space of 0'20 

 inch, while about 18 occupy the same space near the aperture ; all, as well as 

 the depressions between, very minutely crenate or granulose. 



Length, l - 30 inches ; breadth, 0-80 inch. 



This species is remarkable for its extremely slender, and closely 

 crowded costae, which are not readily seen at a little distance ; and it is only 

 nnder a good magnifier that the very minute crenulations can be seen. The 

 spaces between the costae are slightly wider than the costae themselves, and 

 apparently marked by minute cross-lines, or crenulations, coincident with 

 those of the costae. Sometimes they appear to be obsolete on the costae, and 

 more distinct in the depressions. It is very distinct from all of the described 

 species known to us. 



Locality and position. Richfield, Summit County, Ohio. Waverley Sand- 

 stone, 50 to 60 feet below the Millstone Grit. 



CoNULARIA SUBCARBONARIA, M. & W. 



Shell very large, very thin, more or less distinctly and nearly equally four- 

 aided, the sides and angles being somewhat rounded, and converging towards 

 the smaller extremity, at an angle of about 18 ; section quadrangular, mesial 

 furrow along each side very obscure, those at the angles distinct ; aperture 

 subquadrangular, or subrhombic and contracted ; lip very profoundly notched, 

 or divided at the angles, so as to form four triangular flaps or appendages, 

 with inflected lateral margins. Surface ornamented with numerous, slender, 

 transverse costae, which arch slightly towards the aperture in crossing each 

 side, without any interruption or backward curve at the obscure mesial 

 sulcus ; costae regularly crenate, and separated by slightly wider depressions 

 near the middle of the shell, but much more crowded towards the aperture ; 

 depressions between the costae, with very obscure transverse furrows, coinci- 

 dent with the crenatures of the costae. . 



Length, about 425 inches ; greatest breadth, measuring diagonally across 

 between opposite angles of an obliquely compressed specimen, l - 63 inches; 

 greatest breadth of one side, 1-23 inches. Number of costae in the space of 

 0*20 inch, near the middle of the shell, 10 ; do. near the aperture, about 20. 

 Number of crenatures in the same space on each of the costae, 20. 



In general appearance, the species of this genus usually present compara- 

 tively little difference, and often they resemble so closely in their ornamenta- 

 tion, as not to be very readily distinguished. Probably the most marked 

 peculiarity of this species is the presence of sharply defined notches in the lip, 

 at the corners, extending down nearly an inch from the margins of the aper- 

 ture, and widening upwards, so as to divide the lip into four subtriangular 

 flaps, which bend a little inwards, so as to contract the aperture, and cause 

 the widest part of the shell to be an inch or more below its upper extremity. 

 Our specimen is not in a condition to show whether these flaps are pointed or 

 truncated at the extremity. 



This species will be readily distinguished from the last by its coarser, and 

 more widely separated, as well as more coarsely crenate costae, even where the 

 deep notches of its lip cannot be seen. 



Locality and position. Keokuk division of the Subcarboniferou3 Series. 

 Warsaw, Illinois. 



CONULARIA WHITEI, M. & W. 



Shell of medium size, tapering at an angle of about thirty degrees. Surface 

 ornamented with distinct, linear, transverse, minutely crenate costae, whioh 

 arch upward, or towards the aperiure, in crossing the sides, and either past 

 without interruption, the imaginary mesial line, or more frequently terminate 

 1865.] 17 



