418 Mr. II. 13. Brady on a 



number of the segments in each convolution difters very widely 

 in the several forms ; but such characters, wliilst they form a 

 legitimate basis for specific or subspecific distinction, cannot 

 be held to possess any higher significance. However this 

 may be, it is clear that any alteration of the trivial name of 

 the* Sumatran species, if alteration be needful, is better left 

 until the publication of the researches of the eminent German 

 observers to whom allusion has been made. 



Fiisulina sphccroidea (Ehrenberg). PI. XYIII. figs. 7-9. 



Borelis sphceroidea, Ehrenberp:, Mikrogeologie, he, cit. 



labyrinfhiformh, id. ibid. 



FusuUna spharica, Abich, M^m. de I'Acad. St. Pt^tersbourg, loc. cit. 



The transition from the elliptical and prolate specimens 

 to the oblate or dnim-shaped, and even to the complanate 

 varieties with rounded margins, is most easy and gradual, as 

 may be seen by reference to figures 5 to 9 inclusive of 

 Plate XVIII. The interval between the two extreme forms 

 might be bridged by a much more numerous series had their 

 connexion needed more copious demonstration. Ehrenberg's 

 drawing oi Borelis spJiairoidea represents a fossil with nearly the 

 contour of fig. 8, or between that and fig. 6, its dimensions being 

 nearer those of the specimen from which the latter was taken. 

 His B. lahyrintJiiformis appears to be only a section of a cast 

 of the chambers of a somewhat similar diaim -shaped form. 



Dr. Hermann Abich, of Tiflis, in his paper " Vergleichende 

 Grundziige der Geologic des Kaukasus," loc. cit.^ describes and 

 figures a precisely similar oblate-spherical variet}'. Through 

 the kindness of Dr. Abich, I have had the opportunity of ex- 

 amining specimens of this form from the Mountain Limestone 

 of Annenia and Azerbeidjan ; and they leave no doubt what- 

 ever on my mind that it is identical with Ehrenberg's species. 

 Not only are the two alike in general external characters and 

 contour, but the internal structure, as far as can be made out 

 (for it is very badly preserved in both), is precisely similar. 

 The size of average specimens from the two localities is about 

 the same, those from the Caucasus probably attaining some- 

 what the larger dimensions. 



FusuUna mqualis (D'Eichwald). PI. XVIII. figs. 10-13. 



Borelis pal<solophus, Ehrenberg, Mikrogeologie, loc, cit, 



palaophacus, id. ibid. 



Orohias aqualis, D'Eichwald, Lethrea Rossica, loc. cit. 



The figm-es in the ' Mikrogeologie ' to which the names 

 Borelis palceolophus and B. palreophacus are appended repre- 



