140 THE FOEAMINIFEEA 



the published figures of this species undoubtedly 

 represent other types of shell structure, as Nuhecu- 

 laria, for certain authors have not recognised these 

 differential characters of the foraminiferal test. 



P. cenomana is said to have occurred in the 

 Lower Lias marls of the West of France. It 

 occurs with some frequency in the Upper Jurassic 

 strata ; again in the Gault and Upper Greensand, 

 and later in certain Tertiary deposits, though rarely. 

 It is, at the present day, most usual in shallow 

 water. (Plate 7, fig. E.) 



Genus CritJdoni72a, Goes. 



Walls of test generally thick, composed of fine 

 arenaceous mud. Normally attached. The interior 

 a simple cavity, or divided by irregular, sometimes 

 by radial, septa. Contour hemispherical, sublen- 

 ticular, or depressed. Apertures few and indistinct. 



On account of the septate interior of several 

 species of this genus it is here regarded as one of 

 the non-labyrinthic Lituolid.e. Recent. 



Example. — Gritliionina mammilla, Goes, ' Kongl. 

 Svenska Yetenskaps-Akad. Handlingar,' vol. xxv. 

 No. 9, 1894, p. 15, pi. iii. figs. 34-36. 



Usually adherent, subglobose, somewhat smooth. 

 Walls thick and spongy. Central chamber sub- 

 spherical, having a diameter equal to the thickness 

 of the walls ; undivided. Apertures few and small. 

 Constructed of fine detrital and argillaceous material. 

 Dr. Goes found his specimens in the Skagerack at a 

 depth of 57 fathoms. It has since been recorded by 



