CARBONIFEROUS CORALS AND BRACHIOPODS 121 
The centres of the autopores are rather less than *5 mm. 
apart, and the interspaces between them usually vary from 
half a diameter up to one diameter. There are however 
a few, much broader areas entirely composed of mesopores 
(“ maculae.”) 
Vertical section : — 
The autopores are cylindrical and somewhat distantly 
tabulate ; the mesopores are very closely tabulate and 
usually separated by well defined v/alls, but, in many 
places, there are no definite separating walls between the 
mesopores, and consequently the autopores lie embedded, 
at such points, in a mere mass of vesicular tissue. 
The corallum apparently formed thin, spreading, attached 
masses. 
[In the absence of a marked trifoliate section to the 
autopores, as well as in the fact that no portion of their 
walls is very strongly thickened, the specimen deviates 
from the most typical members of the Fistulipora group 
and approaches near to Heliolites ; but the absence of 
regular septa and the frequent suppression of the wails 
between the mesopores renders it most probable that its 
place is with the Monticuliporoids rather than with the 
Corals. I have consequently referred the specimen to 
that species of Fistulipora in which the characters of the 
genus are least exaggerated.] 
The figure shows the horizontal section magnified three 
times lineally. 
III. DESCUIPTIOlsr OF THE BRACHIOPODS. 
Teretrat blid s . 
Dieiasma. 
Dielasma hastata, Sow. 
There is one specimen, labelled “ Clifton,” which has 
