226 Vniversity of California Puhlications in Zoology. [Vol. 8 



Ventral area does not indent the epitheca, its anterior part much 

 restricted, the middle region very narrow, and the posterior part ellip- 

 tical, the whole having the shape of a short-handled spoon with a sigmoid 

 handle. The narrow apical 1' appears to continue the ventral area to the 

 apical region. 



The plate formula is 3', 0", 6", 6, 6'", IP, 1"". The ventral apical 1' is 

 very slender about 0.3 girdle width across, bent to the right in the 

 middle of its course. It bears a median line of pores and carries at its 

 apex an elliptical closing platelet. The ventral pore is an elliptical 

 structure on the median margin of plate 3'. Plates S' and 3' are almost 

 bilaterally arranged upon the left and right sides of the apex. Pre- 

 cingular 6" is displaced posteriorly nearly to the level of the proximal 

 end of the anterior girdle list and is plainly quadrilateral in form. Post- 

 cingular 1'" is very short, scarcely a girdle width in length. Posterior 

 intercalary IP widens posteriorly to nearly two girdle widths. Antapical 

 I"" is deeply indented by the ventral area. The anterior plate of the 

 ventral area is small, not indenting the epitheca and bearing the flagellar 

 pore on its posterior margin. The intermediate plates are hidden in the 

 constricted part of the area. The posterior plate is elliptical with a 

 group of pores at its posterior part. 



The surface, in well-developed thecae, is rather strongly marked by 

 prominent longitudinal striae which stand out from the minor mesh work 

 most clearly in the precingular series of plates, and less so in the apical 

 region and the distal part of the postcingular zone. About ten major 

 lines may be counted across the ventral face. Between these lines a 

 minor network breaks up the surface into irregular polygons, or areoles 

 in a few of which pores of irregular sizes may be detected. The number 

 of pores is ten to fifteen in each major plate of the precingular and post- 

 cingular series. The girdle plates are coarsely and unevenly porulate. 

 Faint traces of intercalary bands may sometimes be detected. There are 

 no spines or lists on this species, as a rule. 



Dimensions: Length, 47/x; transdiameter, 37/i,; width of 

 girdle 5/i,. IMurray and Whitting (1899, pi. 28, fig. 4) figure an 

 individual 35 by 28/i,. 



Variation : Varies considerably in the development of sur- 

 face markings, in the width of precingular 6", and somewhat in 

 the development of an apical elevation, all features tending 

 toward G. poly gramma, the next member of the series in this 

 group. 



Comparisons : The linear markings and absence of apical 

 horn and of antapical spines distinguish it from members of the 

 G. spinifcra group, and the last two characteristics and its smaller 

 size serve to separate it from G. polygranima. The absence of 

 overhang separates it from G. scrippsae. 



Synonomy : The form described by Faure-Fremiet (1908) 



