182 THE FOEAMINIFERA 



Genus Clieilostomella, Reuss. 



Segments oval, placed alternately at either end of 

 the test. Aperture a curved slit, sometimes gaping, 

 situated to one side, and at the junction of the 

 penultimate and the final chamber. In recent speci- 

 mens the test is thin and sparsely perforate ; in fossil 

 examples it is thicker and the perforations are 

 difficult to make out on the polished shell surface. 

 Tertiarij {Eocene) to Beceiit. 



Example. — G. ovoidea, Reuss, ' Denkschr. d. k. 

 Ak. Wiss. Wien,' vol. i. 1850, p. 380, pi. xlviii. figs. 

 12, a-e. 



The figure of the recent example, reproduced from 

 Mr. Millett's drawing, shows the arrangement of the 

 chambers rather distinctly on the outer shell surface. 

 The fossil specimens are as a rule more regularly 

 ovoid in outline, save for the apertural portion of the 

 shell, which is sometimes salient, or spouted. The 

 oldest formation in which this species appears to have 

 made its appearance is the London Clcuj ; and in the 

 material from Piccadilly the little egg-shaped tests 

 are not uncommon. It is also a characteristic fossil 

 in various Oligocene strata in North Germany and 

 Austria, in the Miocene of Vienna, and the Miocene 

 and Pliocene of Calabria. It is a w^ell-distributed 

 form in our existing seas. (Plate 10, fig. B.) 



Genus Seahivol-ia, Beady. 



Test free, hyaline, perforate ; composed of a 

 number of chambers, each enclosing, partially or 



