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CRETACEOUS FORAMOIFERA. 47 



Operoulina cotoplanata var. granulosa.l 



Operculina granulosa. B, 12, a, b, c. "Cette petite operculine, que Ton trouve 

 dans les memes gisements que la precedente, nous parait devoir en etre separee. 

 Elle est constamment plus petite ; ses cloisons, qui se montrent enformant un leger 

 relief a la surface du test infiniment mince qui renferme les spires, sont ici proportion- 

 nellement plus serrees. Cette espece tres plate se compose de 3 a 4 tours de spire. 

 Elle porte a sa surface, de chaque cote, un certain nombre de fines granulations qui 

 se trouvent irregulierement distributes sur les petites cotes en relief qui correspond- 

 ent aux cloisons interieures. Ces points saillauts, rares sur les derniers tours, se 

 trouvent agglomeres au centre chez beaucoup d'individus. Diametre, 4 a 5 millim." 



Operculina granulosa. B, 12 a, b, c. This little Operculina, which is found in the 

 same layers as the preceding (0. ammonea), appears to us worthy of separation. It 

 is uniformly smaller ; its partitions, which form a slight relief upon the surface of 

 the veiy thin shell which encloses the whorls, are proportionally more approximate. 

 This species is very flat, and is made up of 3 or 4 spirals. It carries on its surface 

 on each side, a number of fine granulations, which are found irregularly distributed 

 upon the little elevations which correspond to the interior partitions. These pro- 

 jecting points, scarce upon the last whorls, are found crowded towards the centre in 

 many individuals. Diameter 4 to 5 mm. 



As there seems to be some doubt and difference of opinion in regard to the species 

 and variety, we will give in addition to the above description the generic diagnosis 

 of H. B. Brady. 



" The test of the typical Operculina is a thin complanate disk, composed of three 

 or four broad convolutions symmetrically arranged and equally visible on both faces. 

 The central portion of the disk is usually somewhat thicker than the outer whorls, 

 and not unfrequently almost umbonate ; the earlier convolutions are more or less 

 embracing, the later whorls evolute. The segments are usually very numerous, of 

 gradually increasing size, and typically very short in the direction of growth, as 

 compared with their uidth radially ; they are for the most part produced on a 

 uniform plan, but near the. finish are often irregular, both as to shape and size (PI. 

 cxii, figs. 3, 4 and 6, Kept. Foram. Challenger). The exterior is sometimes smooth, 

 but, more frequently, either the sutures or the surface of the chambers, or both, are 

 ornamented with exogenous granules, papilUe or tubercles, which, as a rule, are 

 njore strongly developed near the centre than on the later whorls ; and in the small 

 northern variety of the genus, the septal lines and periphery are distinctly limbate. 

 The general aperture is a straight or slightly curved fissure at the inner margin of 

 the final segment, close to the periphery of the previous convolution ; but the test 

 has frequently also a number of secondary orifices, in the form of small circular 



