RMzopodal Genera Webbiiia and Vitriwebbina. 331 



affinity towards Nuhecularia^ but not to Wehhina in this 

 respect. 



That Webhina is a genus closely allied to Trocham- 

 mina is evident when a thin section is examined under a 



Fig. 2. 



Portion of the test of W. clavata more liigbly raagnitied. X 360. 



a recent specimen of W. clavata ; and it shows the arenaceous 

 central layer glazed over internally and externally, the 

 outer glazing being smoother, more evenly laid, and paler 

 in colour than the inner. The median arenaceous layer 



Fig. 3. 



Vitriivebbina Icsvis (Sollas). Chalk, Chariug, K«mt. X 20. 



averages about "027 millim. in thickness and the inner 

 and outer layers about "002 millim. each. There is also 

 much chitinous material between the angular sand-grains and 

 spicules, and the outer and inner layers of the shell are 

 composed of the same substance. The grains of sand average 

 •014 millim. in diameter. 



In the specimens of Vitriwebbina which exhibit the 

 secondary septation before referred to the first segment 



