414 Transactions of the Society. 



paper,* describe under the name P. subnodosa (Reuss) some 

 specimens which are unquestionably similar to ours, for in the 

 figures they give sections of the shell in which the central column 

 is most distinctly shown. Their description is as follows : " The 

 small initial chamber is oval, and the succeeding chambers are not 

 compressed, but have a depression immediately beneath the apex 

 in which is situated the crescentiform aperture. From this 

 aperture a two-layered column reaches to the base of the shell, by 

 which the aperture itself is contracted into a sickle-shaped slit. 

 The two layers of the column unite in the adult shell, forming a 

 hollow rope (hohlen Strang), which traverses the entire length 

 of the shell. The succeeding chambers embrace their predecessors, 

 being stouter on the side which bears the aperture, and develop- 

 ing an aperture on the side opposite to the last. The arrangement 

 of the chambers becomes in this way irregularly biserial. On the 

 surface of the shell the chambers are divided by deep sutures. 

 The whole appearance of the shell is not unlike that of many of 

 the Polymorphinre, whose finely porous shell-structure is similar 

 to that of the Pleurostomella. The most important difference lies 

 in the aperture and in the presence of the vertical column 

 (Langsroh/re). 



"The chambers number 8 to 11. The length of the shell, 2*8 

 to 4*0 mm. The diameter at the small end is 0'3G to 0*45 mm., 

 and at the oral end • 90 to 1 • mm. The diameter of the inner 

 tube (Bohrer) is 0'036 to 0*091 mm. The specimens figured by 

 Reuss are identical with those from Aix, even to the swollen 

 edges of the aperture, but they are hardly more than one-third of 

 the size of the latter, whilst they agree with them in the number 

 of the chambers." 



We propose for our specimens a new genus under the name 

 Ellipsoidella, and to place it in Brady's sixth Family Chilosto- 

 mellidre. In spite of the difference in size in our specimens we 

 do not think that they represent more than a single species, though 

 they may possibly represent this species in a dimorphous form. 

 Nothing can, however, be decided on this point until the discovery 

 of further specimens permits of a more detailed examination than 

 has at present been practicable. 



Family CHILOSTOMELLID^. 



Genus Ellipsoidella g.n. 



Test free, cylindrical, the earlier chambers somewhat compressed 

 and arranged in an irregularly triserial or biserial manner, the 

 later chambers nodosarian ; aperture a terminal crescentic slit, 



* Die Poram. dor Aachener Kreide. Abhandl. der Konig. Preuss. Geolog. 

 Landesanstalt, n.s. pt. 3, p. 64, pi. xii. figs. 30-38, 1891. 



