6o4 TRANS. ST. LOUIS ACAD. SCIENCE. 



Ehinopora venosa, nov. sp. 

 Plate 7. Fig. 3. 



Frond, consisting of a calcareous crust, expanded over the 

 surface of several centimetres area. The surface is crowded with 

 rounded cells, raised into conspicuous papillse and arranged in 

 diagonal rows. The whole frond is strengthened by a strong 

 system of bifurcating rounded network of veins, which is itself 

 marked with oval cells. Veins are about one millimetre in di- 

 ameter, and situated several times that distance apart, with about 

 24 oval cells in the length of a centimetre. The papillose cells 

 are one-third of a millimelre in diameter, and the rows of these 

 cells are separated by depressions one-fourth of a millemetre in 

 width. 



Forviation and Localily. — It occurs in the shaly-calcareous Clin- 

 ton rocks at Hamilton, Ontario. 



Clathropora(?) gracilis, nov. sp. 



Plate 7. F'Jg. 4.* 



Stems cylindrical below, enlarging rapidly above, and dividing 

 into two or four flattened branches ; frond apparently poriferous 

 on both sides ; apertures of cells more or less quadrangular, rhom- 

 boidal or oblong, and arrranged in series parallel to the direction 

 of the stems, and near the base in quincunx order. This species 

 resembles fragments of Clathopora alcicornis, but differs from it 

 in that the stem tapers to a minute base, and in the character 

 of the pores, which are very minute, there being longitudinally 

 about three in the length of a millimetre, and ti"ansversely about 

 five rows with their separating linear ridges in the same meas- 

 urement. The largest specimen obtained measures three centi- 

 metres Irom base to broken summit (divided into two branches 

 at about one centimetre from base), and three millimetres at great- 

 est breadth of branch. 



Fortnation and Localiiy. — This species is found associated with 



fragments of Trilobites in the earthy blue dolomites just below 



the "chert-beds" of the Niagara formation, at Hamilton, Ontario. 



Fenestella bicornis, nov. sp. 



Plate 7. Fig. -2. 



Frond long and slender, consisting of a single stipe, making 

 two nearly equal divisions about midway between base and sum- 



* Fig. 4 is not a good representative of the markings. 



