JO HALKYARD, Fossil Foraminifera of the Blue Marl 

 150. [Ellipsoidina lorifera, sp. nov.] 



I50A. NODOSARIA (DENTALINA) LORIFERA, Sp. nOV. 

 PI. IV, fig". 2, 3 . 



Test consisting" of 8 to 12 oval segments, sutures depressed; 

 aperture, a curved or straight slit situated at the extremity 

 of the final segment and placed transversely in respect to the 

 plane of curvature of the shell. Each segment provided inter- 

 nally with a median band or flat pillar of shell-substance, con- 

 necting the margin of each oral aperture with the one preceding 

 it. Length, .85 to 1.45 mm. 



This species is frequent in the Biarritz Marls. Externally 

 it resembles somewhat D. lorneiana, d'Orb., but when the shell 

 is broken open, or is sufficiently transparent to observe the 

 internal structure, it is seen to possess a very remarkable fea- 

 ture. In viewing the shell mounted in Canada balsam by trans- 

 mitted light the central longitudinal band or strap is very easily 

 visible but may be supposed to be a tube. It is only by carefully 

 breaking up specimens that the true nature of the structure can 

 be really seen. The band (or much flattened pillar) is generally so 

 placed that its broader surface is parallel with the slit-like oral 

 aperture of the shell, close to the internal margin of which it 

 is attached; in rare cases, however, the broad surface may be at 

 right angles to the length of the orifice, in which case it is 

 bifurcated, one of the two divisions or prongs being attached 

 to one side of the aperture, and the other prong to the opposite 

 side, so as to form a bridge over the orifice. 



The central pillar is not always straight but often flexuose 

 and is broadest at its point of attachment. The function is not 

 evident as it is much too delicate to be of any use as a support, 

 or means of strengthening the shell, being thinner than the shell- 

 wall in all the specimens I have examined, and moreover not 

 being of good suitable form. If the structure had been colum- 

 nar or even tubular there might have been some reason to 

 suppose it to fulfil the same purpose as the columns in Ellipsoi- 

 dina, which seem to exist for the purpose of strengthening the 

 test. D'Orbigny figured (Foram. Foss. Vienne, pi. II, figs. 

 48-51) under the name of Lingulina rotundata a Nodosaria of 

 the radicula type having a slit-like aperture instead of the 

 circular or stellate orifice usual in that genus. Judging from 

 the peculiar form of aperture, which is similar to that of N. 

 lorifera, it is quite possible d'Orbigny's species may be also 

 furnished with a similar internal structure, though nothing to 

 that effect is noted in the author's description. 



