On BenuUna Sorhyana. By J. F. Blake. 263 



doubt of their being the same. These new examples settled one 

 question with certainty. There could be no longer any doubt 

 that they were originally hollow, for these were easily broken by 

 pressure, and then presented their two empty halves, like a broken 

 egg-shelJ, as plainly as possible. 



Another point less doubtful before was also proved, namely, 

 that they had been originally calcareous, because these are so. 

 Silex may replace carbonate of lime, as it had done in the specimens 

 from Filey, but the process cannot well be reversed. I conclude 

 therefore that these Sturminster specimens are in their original 

 condition. Acidulated water appears, however, to have had access to 

 them, as their surfaces are eaten away and more or less rugged. 

 This perhaps suggested the idea which my friend Professor Kupert 

 Jones kindly favoured me with, that if Foraminifera, they might 

 belong to the Saccamina group. Treated with hydrochloric acid, 

 they certainly leave a small residue, which, however, appears to be 

 structural silex and not grains of sand. The presence of such a 

 residue would certainly not prove them to be arenaceous Foramini- 

 fera, for the undoubted Dentalines, Marginulines, &c., of the same 

 deposit also leave a small residue, while the true arenaceous forms 

 are almost if not entirely untouched. I have been fortunate, 

 however, in being able to obtain what I think to be further evidence 

 of their structure and nature. In a deposit of clay at Hilmarton, 

 near Calne, Wilts, belonging to the uppermost portion of the 

 corallian beds, and therefore of very similar age to the former 

 deposit, I found a few among tbe ordinary Foraminifera of the 

 washing which appear to have undergone but little change. These, 

 however, do not make up the bulk of the microzoan fauna as at 

 Sturminster and Scarborough, but are rare in comparison. Like the 

 others, they are hollow and dissolve in hydrochloric acid, but their 

 surface is less destroyed. As they now are, they appear to have 

 two layers, an external one more opaque, which is mostly broken 

 away, and an internal one more transparent. The external coat 

 appears to me not to belong to the original shell, but to be a sub- 

 sequent deposit. However, in some it presents in places an areo- 

 lated structure, that is to say, is dotted over quincuncially by little 

 pits. The internal layer shows, as I think, a foraminated structure 

 hke the shells of Eotalines ; but as the appearance is by no means 

 distinct and cannot often be seen, I confess it might be more satis- 

 factorily demonstrated. In some these foramina seem to be limited 

 to the neighbourhood of certain lines forming a pattern on the 

 shell, and not to be uniformly scattered over the surface. The areo- 

 lation of the external layer when present is more certain, and my 

 idea of its meaning is that the calcareous matter has collected 

 on the interspaces between the true foramina below, making these 

 latter more conspicuous, though in some places it has covered foramina 



