NUMMULITES. 365 



Characters. — Discoidal, compressed, compact; chambers fewer than in Op. 

 complanata, and subquadrate ; the limbation of the septa gives the surface a 

 rotiform aspect. 



Occurrence. — Operculina ammonoides has a wide geographical range, but is for 

 the most part confined to comparatively shallow waters. It has been met with 

 in the North Atlantic, including the Baltic, Gulf of Gascony, and Mediterranean ; 

 Gulf of Suez, off the Mauritius, Gape of Good Hope, and Australia; Malay 

 Archipelago, the Philippines, Hong Kong, and south of Japan. 



Fossil specimens have been recorded from the Pliocene of Calabria (Seguenza), 

 and from the Pleistocene of Norway (Sars). In the Coralline Crag we have 

 specimens from Broom Hill, zone d, Sutton and Gedgrave, zone f. 



2*. Operculina ammonoides (Gronovius), 1781; var. curvicamerata, nov., Jones. 



Plate V, fig. 33. 



This differs from Op. ammonoides, vera, in not having a septate limbation, in 

 the narrowness and curvature of the chambers, and in its distinct margin. It 

 is proposed to distinguish this as a variety under the name of curvicamerata. 

 Probably from the Crag at Sutton. 



Dr. A. Goes in 1894, ' Trans. Roy. Swed. Acad.,' figured a form intermediate 

 to this and Op. ammonoides in his pi. xvii, figs. 833 a — c. 



Genus 3. — Nummulites, 1 Lamarck, 1801. 



The following are references to some of the most important memoirs treating 

 of the history and particulars of this genus : 



UArchiac et Haime, ' Description des Animaux fossiles du Groupe Nummuli- 

 tique de l'lnde,' livr. i, 1853; livr. ii, 1854. 



Parker and Jones, 'Annals and Magazine of Natural History,' ser. 3, vol. v, 

 1860, pp. 106—111 ; pp. 289—294; vol. viii, 1861, pp. 230—238. 



Carpenter, ' Introduction to the Study of Foraminifera,' Ray Soc, 1862, 

 pp. 262—276. 



Philippe de la Harpe, ' Bullet. Soc. Geol. France,' ser. 3, vol. v, 1877, 

 pp. 817—835 ; ■ Bullet, de la Societe de Borda a Dax,' annee iv, 1879, pp. 137— 



1 This name lias priority over Nummulina, Lamarck. It was at first intended to distinguish 

 fossil from living forms by making the names of the former end in ites, and those of the latter in ina. 

 As fossil specimens were first recognised Lamarck named them Nummulites ; d'Orbiguy published 

 some recent examples with the name Nummulina, but this is of use only as a synonym (see ' Catal. 

 Foss. Foraminifera Brit. Mus.,' 1882, pp. 90, 91). 



