Palaeozoic Corals and Foraminifera. 123 



bothj and separate them at a glance from the three other pub- 

 Kshed species. 



Common in the carboniferous Hmestone of Derbyshire, form- 

 ing subcyhndrical masses 3 or 4 inches long. 



{Col. University of Cambridge.) 



Michelinea grandis (M'Coy) . 



Sp. Char. Corallum widely conic, the width considerably exceed- 

 ing the height, externally marked with thick, rounded, radia- 

 ting ridges, finely wrinkled across ; polygonal cells, on the 

 upper convex surface, averaging 5 to 8 lines iu diameter (most 

 near the former at a height of half an inch, most near the 

 latter size at a height of 2 inches), very deep with thin walls 

 not coated by vesicular plates, but having numerous distinct 

 foramina and many longitudinal strise within ; internal vesi- 

 cular plates small, very thin, much curved, forming nearly 

 horizontal rows of vesicles at the bottom of the cells. 



This fine species is most allied to the M. tenuisepta (Phil, sp.), 

 but is distinguished by the much wider conical form of the mass 

 and by the cells having, on an average, a diameter three times 

 greater at the same height than in that species, of which I have 

 examined many specimens both British and foreign, and find the 

 figures of Michelin and Koninck, as well as of Prof. Phillips, exact 

 in this respect. Young specimens (1 to 2 inches in diameter) 

 slightly resemble the M. favosa (Gold, sp.) in form, having the 

 base much flatter than in the adult, but on comparison with 

 authentic Belgian specimens they are found to be distinguished 

 by the large rounded radiating ridges on the exterior, of which 

 no traces exist in that species, as may be also seen from the 

 figures of Goldfuss and Michelin ; the cells also of the present 

 species are, even at that stage, larger, and increased growth de- 

 stroys, all resemblance. The M. megastoma (Phd. sp.), which 

 has large cells (although much less than the present species), is 

 distinguished by its mode of growth, it forming lai'ge flattened 

 expansions; internally its vesicular plates are much larger, fewer, 

 and highly inclined at the circumference, coating the walls of the 

 cells to their very edge, giving them a peculiar thick tumid ap- 

 pearance, which may be imperfectly recognized in the w^orn 

 specimen figured by Prof. Phillips, but which distinguishes 

 even fragments from the other four species. Average height of 

 the conical masses 2|^ inches, width 3^ inches. 



Very common in the carboniferous limestone of Arnside, 

 Kendal. 



{Col. University of Cambridge.) 



