Recent and Fossil Foraminifera. 329 



Bigenerina d'Orbigny. 



G6. Bigenerina conica sp. n. Plate XVI. 



Clavulina eoctena (G-iimbel), Terquem, 1882, Mem. Soc. Geol. France, ser. 3, 

 vol. ii. Mein. Til. p. 121, pi. xii. fig. 35 a, b. 



Among the specimens from the shore-sands were found three 

 which presented considerable difficulty in identification. Follow- 

 ing Terquem's figures (supra) we were at first inclined to allot 

 them to the species Clavulina eocxna (Giimbel), but a reference 

 to Giimbel's original figure and description convinced us that 

 Terquem's identification of his specimen was incorrect, and, as we 

 have been unable to identify the form elsewhere, we now describe 

 it under the above name. The aperture and other characteristics of 

 the shell are such as to show it to be a true Bigenerina. Terquem's 

 description is as follows : — " Shell short, nail-shaped (forme de clou), 

 conical, very rough, oval in transverse section, truncate in front, 

 obtuse behind, formed of chambers first of all spherical, very small 

 and heaped together. The later ones (6-8) very pronounced and 

 arranged in superimposed rings. Sutures large and deep ; aperture 

 oval. Loc, Vaudancourt. Frequent." 



This description agrees in nearly all respects with our speci- 

 mens, except that the sutural lines, though readily distinguishable, 

 can hardly be described as " pronounced," and the surface rugo- 

 sities referred to in the description are really blunted or broken 

 spines. 



The assignation of this form to Bigenerina might not have been 

 so certainly decided upon — in view of the few specimens found in 



EXPLANATION OF PLATE XVI. 

 Bigenerina conica sp. n. 



Fig. 1. — A specimen (fossil) from Selsey. 

 ,, 2. — Front view, showing aperture and tubular spines. 

 ,, 3. — Side view. 

 ,, 4. — Oral view. 

 ,. 5. — A front view of balsam-mounted specimen. The dark central portion 



shows the so-called " siphon," extending from floor to roof in central 



part of each chamber. 

 ,, 6. — Diagrammatic. Longitudinal median section, showing the nature of the 



tubular spines and of the so-called " siphon." 

 ,, 7. — Diagrammatic. Horizontal median section through a chamber. The 



partition, or " siphon," is shown in section in the middle of the cavity, 



the oral opening leading to the next chamber being darkly outlined 



above it. 



Figures 2, 3, 4, 5 are drawn from Moorabool River specimens. 

 All figures magnified 110 diameters. 



