DESCRIPTION OF CHALK CORALS. 315 
proximal margin of the aperture. The specimen submitted to examination by 
Mr. Dixon incrusted an Ananchytes, which was found by the Marquis of North- 
ampton in a chalk-pit at Houghton ; and it afforded some additional informa- 
tion to the account of the genus already published. In the remarks on Escha- 
rina? intricata, allusion is made to certain corals figured by Goldfuss' as Celle- 
pore, but assigned to Marginaria by Herr Roemer, and characterized, so far as 
delineated, by having the interior of the cell completely exposed, as well as its 
outer limits defined by a furrow. The coral immediately under examination 
afforded many examples of similarly uncovered cells, the defect being however 
evidently due to injury ; besides innumerable tracings or lace-like ground-plans 
from which all superstructures had been removed by abrasion ; but it gave also 
instances near the margin of some portions of the specimen of cells equally open 
from immaturity, and others with a narrow lamina at the proximal end, indica-— 
ting that the covering was commenced at the extremity and not laterally. 
Another point on which the specimen supplied information, and one of greater 
importance, was the existence of gemmuliferous or ovi capsules. These structures 
were of limited occurrence and smal! dimensions. ‘The form was semi-globular 
(fig. 7b), and they were entirely situated on the surface of the next cell, leaving 
the mouth of that with which they were functionally connected totally free from 
impediment. ‘Their own aperture was a small segment of a circle. _ It may be 
further stated, that the specimen which was distributed over a large portion of 
the Ananchytes, exhibited no external changes due to age, the furrows remaining 
constantly well defined ; nor were any satisfactory examples detected of a normal 
filling up of the mouth. 
Very few remarks respecting minor details can be submitted to the reader’s 
consideration. The cells in regularly developed portions (fig. 7 @) were arranged 
with great uniformity in alternate rows, and exhibited considerable agreement in 
size and shape, exactly adapting themselves to the outline of those immediately 
adjacent. The length of the cells was rather less than a third, and the greatest 
breadth was about one-eighth of a line, the mature aperture occupying half the 
area. Where the growth of the coral had been greatly disturbed, the deviations 
in form and construction were often so considerable as to present no resemblance 
to the normal condition, exhibiting sometimes a slightly concave or convex sur- 
face with a central foramen or no mouth, and in other cases an outline approach- 
ing that of a spherical triangle (fig. 7c). The boundary furrows did not penetrate 
‘ Petref. Cell. velamen, tab. 9. fig. 4, and C. bipunctota, tab. 9. fig. 7. 
