NATURAL SCIENCES OF PHILADELPHIA. 



Leptopora typa, n. sp. Polypary subcircular in outline, and slightly con- 

 vex on the general surface ; composed (in the specimens examined) of 25-30 

 rather large cells, of which the internal ones are hexagonal, and the peripheral 

 rounded exteriorly ; margins of cups strongly elevated ; radial lamellae 

 about 20. 



Diameter of mass '72 -,* diameter of the cells about -14, and their depth 

 about -07. In a specimen whose diameter is 1-27, tbe diameter of the cells 

 is -22. 



Ranges from the oolitic bed No. 6 into the base of the Burlington lime- 

 stone. 



This singular coral is not as well known as is desirable. Though discoid, 

 it. does not seem to be encrusting. No diaphragms or communicating pores 

 have yet been detected. 



TREMATOPORA, Hall. 



Trematopora? vesiculosa, n. sp. Corrallum delicate, terete, branching, 

 celluliferous on all sides. Cells arranged in spiral and often longitudinal 

 series ; cell-mouths oval, slightly elevated on the lower margin, the longitudi- 

 nal series more or less separated by a straight or flexuous, sharply-raised 

 carina. Surface between the cell-mouths imperforate, but the substance of the 

 corallum beneath is irregularly vesicular. No solid axis exists, the cells ap- 

 pearing to ascend and diverge gradually from an imaginary axis. 



Diameter of stem about -05 ; length and breadth of cell-mouth -02 and -01 ; 

 distance between the cell-mouths in the spiral series -01. In some specimens 

 the cell-mouths are somewhat more widely separated. 



Base of the Burlington limestone and in the fine grained sandstone of Ohio. 



Trematopora ? fragilis, n. sp. Corallum delicate.branching.terete or slightly 

 compressed at the bifurcations, celluliferous on all sides. Cell-mouths minute, 

 oval, somewhat remote, not disposed in regular series, more approximate in a 

 transverse than in a longitudinal direction. Intervening surface imperforate ; 

 the substance immediately beneath minutely cellular. 



Least distance between contiguous cell-mouths about equal to their transverse 

 diameter; greatest distances two or three times as great. The absolute di- 

 mensions of the cell-mouths are less than in the last species. 



Base of the Burlington limestone. 



The two species above described are only provisionally referred to Trema- 

 topora. They belong to a group often ranged under Millepora and Ceriopora, 

 but apparently without sufficient reason. The assemblage of branching (or 

 sometimes foliaceous) corals without septa or lamellae, ranging from the lower 

 Silurian into the Carboniferous limestone, seems to be but imperfectly understood; 

 and the generic and even more fundamental relations are in a state of very 

 unsatisfactory vagueness and confusion. 



LINGULA, Bruguiere. 



Lingula membranacea, n. sp Shell flattened, quadrate-ellipitical, nearly as 

 broad near the beak as at the same distance from the anterior margin ; length 

 nearly equal to twice the width ; lateral margins slightly curved ; beak 

 scarcely elevated, near the posterior margin, but with a narrow belt behind it. 

 Shell substance membranaceous, marked externally by very delicate, regular 

 concentric lines. 



Length '50 (100); breadth in the middle -32 (64) ; breadth at one-fourth the 

 shell-length from posterior end -28 (56); breadth at same distance from anterior 

 end -31 (62). 



Differs from L. concentrica, Hall, from the Genesee slate by its subequal 



* The measurements in this paper are given in inches. Where one number is followed by 

 another in parenthesis, the latter is the relative measurement the dimensions which is generally 

 the greatest being assumed 100 



1863.] 



