250 CALIFORNIA ACADEMY OF SCIENCES. [Proc. 3D Ser. 



Cristellaria Lamarck [1816]. 

 Cristellaria cassis (Fichtcl & Moll). 



Plate XXIX, Fig. 18. 



Nautilus cassis Fichtel & Moll, 1798, Test. Micr., p. 95, PI. XVII, figs. 



a-l. 

 Cristellaria cassis Lamarck, 1816, Tabl. Encycl. et Method., PI. 



CCCCLXVII, figs. 3 a-d. d'Orbigny, 1825, Tabl. Metli. CC-phal., 



p. 124, No. 3. Brady, 1884, Chall. Rapt., Vol. IX, pp. 552, 553, PI. 



LXVIII, fig. 10. FoRNASiNi, 1893-94, Mem. R. Accad. Sci. Bologne, 



Ser. 5, Vol. IV, p. 221, PI. Ill, figs. 21, 21a; p. 222, PI. Ill, figs. 22, 23. 



A. SiLVESTRi, 1899, INIeni. Accad. Pont. Lincei, Vol. XV, pp. 206-212, 



PI. VII, figs. 13-17. 



This species is extremely variable and has been described 

 under as many names as its variations. The specimens are 

 very like some figured by Dr. A. Silvestri from the Pliocene 

 of Siena. They are devoid of the beaded ornamentation, 

 are much compressed, and have the sutural margins at the 

 periphery terminating in a point which gives a serrate aspect 

 to the shell-margin. 



C. cassis is found in most Tertiary deposits, and at the 

 present time appears to be restricted to fairly shallow de- 

 posits of tropical or warm temperate areas. 



Santa Clara County, California; common. 

 Cristellaria miocenica, sp. nov. 



Plate XXX, Figs, i and la. 



Test subcircular or suboval, much compressed. The sutural lines reflexed; 

 septa thick and swollen on surface. A distinct umbilical depression is ob- 

 servable in nearly all specimens. Average breadth of test, .87 mm.; thick- 

 ness, . 16 mm. 



This species most nearly resembles C. complanata 

 Reuss,^ but the latter species is in outline of the C . crepi- 

 dula type, whilst C . miocenica belongs to the more discoidal 

 type of C . rotulata. The specimen here figured is one of 

 the more lengthened forms. 



Santa Clara County, California; common. 



1 Verstein. bohm. Kreidef., 1845-6, Pt. j, p. 33, PI. XIII, fig. 54. 



