Genus Orbitoides of d' Orhigny. 441 



d'Orb. (op. et loc. cit.), and therefore to apply the term "Orbi- 

 toides dispansa " indiscriminately to the two fossils, viz. 

 Lycopliris epMpinum and L. dispansuSj may be a mistake ; 

 while if they really belonged to the types that I have men- 

 tioned respectively, it may be inferred that both are found 

 together in the bed of Nummulites at Lukput, in Cutch, from 

 which these fossils are stated by Captain Grant, in his 

 " Memoir," to have come [op. et loc. cit). 



For excellent illustrations of the microscopical structure of 

 Orbitoides papyracea and all the known species of this type 

 brought together I must refer the reader to Giimbel's " Bei- 

 tiagezur Foraminiferenfauna der Nordalpinen Eociingebilde," 

 Taf. iii. n. iv. (Abhandl. k. bayer. Ak. Wiss. vol. x. p. 581, 

 1868), whereby he will become acquainted with this type. 

 Thus the reader will observe here, no less than in Sowerby's 

 delineations of his Lycophris ephifpium^ to which I have 

 alluded, that horizontally the central plane is composed of 

 more or less oblong rectangular chambers, and that vertically, 

 that is on each side of the central plane, the crust-like struc- 

 ture is composed of columns of vertically compressed cells 

 intermingled with conical columns (which columns consist of 

 non-tubular, opaque, white shelly substance), whose obtuse 

 ends project above the surface in the form of little knobs 

 and whose pointed ones extend down to the central plane 

 (Giimbel, op. et loc. cit. Taf. iii. fig. 21). 



On the other hand, equally typical microscopical illustra- 

 tions of Morton's Nummulites MantelU from the Claiborne 

 beds of Alabama, with the exceptions just stated, are repre- 

 sented in d'Orbigny's illustrations of the structure of his 

 Orbitoides media {op. et loc. cit.), whereby the reader may 

 become equally well acquainted with the prevailing type 

 of this Orbitoid structure as with its differences from that 

 of Orbitoides papyracea. Thus it will be observed here in 

 Nummulites MantelU, no less than in my own illustrations of 

 the Sindian species of 1853 ('Annals,' vol. xi. pi. vii. 

 figs. 40 a, 5, c, and 41), that horizontally the central plane 

 appears to be composed of circular, or, from their juxta- 

 position, slightly hexagonal cells, so arranged in the inter- 

 stices of obliquely crossing lines that, radiating centrifugally 

 from the centre to the circumference, they present the pattern 

 of an " engine-turned " watch-case (see especially d'Orbigny's 

 illustrations of his " Coupe horizontale " of Orbitoides media), 

 and that vertically here the crust-like structure is composed 

 of columns of vertically compressed cells, which are not inter- 

 mingled with the " conical columns " before mentioned, but 

 are separated from each other simply by the translucent sub- 



