282 Messrs. Parker and Jones on 



keel. Fig. 46j -A/ow^ow^Ma HempricJni (^) j is a true Botah'a, 

 very near B. Beccariij var. ammoniformis. Fig. 47, Planu- 

 lina^ umhilicata, appears to be Cy-tst. cultrata ; also figs. 48, 

 PL'? mwpla^ 49, PZ.? invaluta^ and 50, P/.? ampUata. Fig. 51, 

 Rotalia auricula, is also a Cristellaria, somewhat produced, as 

 is common in connexion with the rapid increase of the seg- 

 ments in size. Fig. 52, Quinqueloculina ? caudafa, is indeter- 

 minable. 



A. The weathered surface of a piece of Egyptian Num- 

 mulitic Limestone. B. Weathered piece of limestone largely 

 composed of " Plamdma pyvamidum " (see fig. 38). C The 

 dust of the Nummulitic Limestone, magnified 300 diameters, 

 part seen by transmitted, part by reflected light : '' no Chalk 

 Morpholites " (Coccoliths). D. Similar dust, but without the 

 finest particles. E. The Nummulites, of natural size : 1, a, Z>, 

 N. placentula ; 2, a, J, c, N, gyzensis ; 3, a, &, c, N. seminulum, 

 which, together with ISl. cellulosus and '"'' Planulina pyrami- 

 diim^'' are easily seen by the naked eye. 



1. Nummulina placentula, Ehr., is the Nautilus major of 

 Forskal (see Ann. Nat. Hist. ser. 3. vol. viii. p. 235), which 

 name was evidently meant for the largest of the common 

 Nummulites of Gyzeh (sometimes 1^ inch across). Some of 

 these are sufficiently large and thin for the typical N, compla- 

 nata, Lamarck (o^;. cit. pp. 232 & 234) ; but Ehrenberg's figure 

 (1, a, h) does not exceed in size some illustrating N.gyzehensis 

 in D'Archiac & Haime's ' Foss. Lid.' p. 94, pi. 2. figs. 6-8. 

 N. placentula {N. major) and N. gyzehensis, therefore, are the 

 same, differing only in size. 



2. N. gyzehensis (Forskal). These smaller specimens, indi- 

 cated by Forskal and figured by Ehrenberg, are probably 

 such as have a large primordial chamber* and relatively great 

 thickness, referred to op. cit. p. 233. N. curvispira, Meneghini, 

 as figured by D'Archiac & Haime, ' Foss. Lid.' pi. 6. fig. 15, 

 is not only one of these subvarieties, but possibly the one 

 alluded to by Forskal and Ehrenberg. 



3. N. seminulum, Ehr., had not been figured by Ehrenberg 

 when D'Archiac & Haime published their important and 

 exhaustive work on Nummulites. There can be little doubt 

 that it is the same as their well figured and described N. 

 Ouettardi (' Foss. Ind.' 1853, p. 130, pi. 7. figs. 18, 19). 



4. "^. cellulosus'''' may possibly Ibe another name for the 

 small forms of N. gyzehensis. 



The Foraminifera shown on plate XXIII. (as those also on 



* This kind of growtli characterizes Ehrenberg's proposed genus Mo- 

 netuUtes, Abhandl. 1856, p. 145, note. 



