140 



PKOP. T. K. JONES ON NUMMTJLITES ELEGANS 



mens from Belgium. N. Prestwichiana (Quart. Journ. Geol. Soc. 

 vol. xviii. p. 93), from the junction-beds of the Bracklesham and 

 Barton series at Alum Bay, may have been mistaken for [on the 

 contrary, was correctly given by Mr. Sowerby as] iV. elegans in the 

 catalogue at p. 85 of the First Edition." 



1879. Writing (October 1, 1879) about some English Nummulites 

 which I had sent to him, Dr. Philippe De la Harpe explained his 

 views about Nummulites wemmelensis, and the variety Prestwichiana, 

 which latter I now refer to Sowerby's elegans ; and he stated that of 

 N. wemmelensis (which, though rare, occurs at Brussels, Jette, Wem- 

 mel, Laeken, Ghent, and Briendereck in Belgium) he recognized the 

 following varieties : — 



1. Type : size 2-3 millim. ; shape irregularly lenticular, with 



knob in the centre ; surface smooth. Wemmel and Jette. 



2. Yar. plicata : size 1J-2 millim. ; shape lenticular, with de- 



pression in the centre ; surface plicated. Ghent. 



3. Var. granulata : size 1^-2 millim. ; shape flat, surface granu- 



lated. Brussels, Park St. Gilles. 



4. Yar. minor : size 1 millim. ; lenticular, smooth, regular. 



5. Yar. Prestwichiana elegans]: size 1-2 millim. ; flat, smooth, 



regular. 



The spire is very nearly the same in all the varieties ; the last is 

 always much larger than the foregoing whorl. By its variations 

 this species has affinities with N. variolarius, with Assilina, and with 

 Operculina *. 



In the 'Catal. Eoss. Eoram. Brit. Mus/ 1882, pp. 91-93, I 

 stated that " the proposed specific name ' N. wemmellensis 9 for the 

 type to which my ' iV. planulata, var. Prestwichiana ' evidently 

 belongs, had such strong justification, that I acceded to the accep- 

 tation of my friend Ernest Yanden Broeck's suggestion. Still, for 

 convenience, the term e Prestwichiana ' has been frequently entered 

 in the Catalogue, as a synonym." It seems now that elegans has 

 priority, if not over wemmelensis, yet over Prestwichiana as one of 

 its varieties. 



This Prestwichiana or elegans is one of the Nummulites which 

 have a large primordial or central chamber, jY. wemmelensis also 

 having the character typically. 



In Belgium the late De la Harpe found eight species, consisting of 

 four pairs of Numniulites, one of each pair having a very small, 

 and the other a large central chamber, thus : — 



Small central chamber. Large central chamber. 



{N. elegans, De la H. (nos. 9 and 11 

 of Sowerby's fig. 2. pi. 538). 2V. 

 planulatus, D'Archiac. 

 2. N lavigatus, Lam. (Type and va- J y LamarcU) 

 rieties scaoer, rotuia, globularms). J ' 

 8. N. Heberti, d'Arch N. variolarius, Lam. 



a -at r\ i- • / rs t n i f wemmelensis, Yanden Broeck ( = 



4. N. Orbignyi {Operculina, Galeotti). j K plamMus ] var . a> vel minor y 



See De la Harpe's letter in the 4 Catal. Eoss. Foram. Brit. Mus.' p. 92. 



