222 U)iiversity of California PubJicafions in Zoology. [Vol.8 



base into the spreading girdle, its altitude 0.75 transdiameters, its sides 

 contracted in a sweeping concave curve into the well-developed apical 

 horn with a slight hump at the apical-precingular suture. Apical horn 

 0.35 transdiameters in height, very obliquely truncated with acute ter- 

 mination on its right margin. Hijpotheca broadly rounded posteriorly, 

 its altitude nearly 0.4 transdiameter, excavated ventrally. Girdle post- 

 median, descending, displaced distally one furrow width. Furrow deeply 

 impressed with stout ridges of body wall. Ventral area is exceptionally 

 wide in this species: it indents the epitheca about a furrow width, flaring 

 posteriorly to the left immediately behind the girdle to 2 and at the 

 slightly convex post margin to 3.8 furrow widths. 



Plate formula, 3', 2", 6", 6, 6'", IP, 1"". Apical region (pi. 11, figs. 

 11-15) consists of a midventral apical (Eautenplatte) 1' widened in its 

 middle to the left to nearly two girdle widths, a short plate on the left 

 dorsal face of the apical horn which cuts off the two anterior intercalaries 

 (1", 2") from contact with the apex, and the right ventral apical 3'. The 

 circular closing platelet (<•/. /)/., pi. 11, fig. 12) is attached to apical 1'. 

 Precingular 6" is quadrilateral and is separated by apical 1' and the 

 anterior plate of the ventral area (ant. pi.) from precingular i'. Post- 

 cingular 1'" is a narrow and sometimes very short plate on the left of 

 the longitudinal furrow; postcingular 3'" is narrower than other members 

 of the series. Posterior intercalary IP is concave on its right margin, ex- 

 panding posteriorh^ Antapical 1"" is 0.75 transdiameter from right to 

 left but narrow dorso-ventrally. The ventral area (v. a., pi. 11, figs. 11- 

 13) is composed of a triangular anterior plate (ant. pi.) crossed in the 

 middle by the anterior girdle ridge and notched posteriorly by the 

 flagellar pore (/?. po., fig. 13). Behind this lie four intermediate plates 

 (int. pi.) and the spreading posterior plate {post. pi.). 



The surface is minutely and quite regularly reticulated with a mesh 

 which sometimes shows a tendency toward a quadrilateral pattern. 

 Pores not demonstrated. Ventral pore (v. po.) near apex on right margin 

 of plate 4'. Girdle without hyaline lists, a very wide (1-1.5 furrow 

 widths) hyaline, faintly reticulated, list on left side of ventral area 

 (pi. 11, fig. 13), arising from suture along posterior intercalary, decnr- 

 rent posteriorly, with an antapical spine (a) on the node where this 

 suture joins the antapical suture. The largest antapical spine (/), 0.33 

 transdiameter in length, arises from the right antapex from the surface 

 of the antapical plate, and a somewhat shorter one (c) from the left 

 antapex. Three or four additional spines {h, d, e) arise at or near the 

 nodes of the antapical suture. The areolation of the surface of the plates 

 extends for a short distance upon the base of the spines. They are, 

 however, solid. 



Contents exceedingly dense, obscuring thecal structure; chromatophores 

 thickly packed. 



Dimensions : Length, excluding spines, 58 to 60/x ; trans- 

 diameter, 34 to 35/1,; dorso-ventral diameter, 20 jx (diameters 

 measured on empty theca, those with contents are less flattened) ; 



