X150 



116 (//5) Outline of the test is essentially circular; 

 periphery is sharp; chambers are obscured by 

 incomplete transverse septa that result in a 

 reticulated appearance of the spiral surface 

 and a narrow fluting around the outer rim of 

 the umbilical surface. Diameter 0.18-0.25 

 mm. a, Spiral view; b, umbilical view; c, 

 edge view Patellina corrugala 



1 16 (115) Outline of the test is not circular, but is notched at the final chamber 117 



117 (116) Test wall is distinctly porous . 

 117 {116) Test wall is finely porous ... . 



.118 

 .119 



118 (117) Umbilical (flat) side is covered by 

 spongelike overgrowth. Diameter 

 0.25-0.50 mm. a. Spiral view; b, 

 umbilical view; c, edgeview "Discorbis" aguayoi 



X50 



118 (117) Umbilical (flat) side is not obscured; living 



specimens are normally attached; umbilical surface \^^ \^ b r^ y ^ ~i^ y g 



is unornamented; umbilical sutures are irregular X75 



toward their inner ends. Diameter 0.32-0.60 



mm. a, Spiral view; b, umbilical view; c, edge 



view Rosalina floridana 



119 (117) Test has an umbilical plug^ 120 



1 19 (117) Test lacks an umbilical plug 121 



'Absence of umbilical plug in some specimens of a species that is characterized by an umbilical plug may be due to breakage and in other specimens, due to 

 environmental influences. For example, see the variant forms of Ammonia beccarii. 



38 



