178 CALIFORNIA ACADEMY OF SCIEiYCES. [Proc. ,^d Ser. 



The following species which have previously been diag- 

 nosed by the writer are here redescribed and figured: 



Genus Cytherea Lamarck. 

 Cytherea (?) Newcombei Mcrriam. 



Plate XXIII, Figs, i and \a. 



Cytherea, sp. nov., Bull. Dep't Geo!., Univ. Cal., Vol. II, No. 3, p. 106. 

 Cytherea Newcombei Merriam, Nautilus, Vol. XI, 1897, p. 64. 



Shell subquadrate to oval, high, moderately thick, truncated anteriorly. 

 Beaks not prominent. Lunule faintly marked. Surface ornamented with 



numerous, irregularly placed growth lines and ridges. On some well pre- 

 served specimens a large number of very faint, radial lines are visible. 

 Length of large specimens 70 mm., breadth 55 mm. Hinge of right valve 

 with three cardinal teeth and a short pit for the anterior lateral tooth of the 

 opposite valve. This pit for the reception of the anterior lateral tooth is 

 shallower and much shorter than in the following species. 



Cytherea Vancouverensis Mcrriam, 



Plate XXIII, Fig. 2. 



Cytherea, sp. nov.. Bull. Dep't Geol., Univ. Cal., Vol. II, No. 3, p. 106. 

 Cytherea Vancouverensis Merriam, Nautilus, Vol. XI, 1897, p. 64. 



Shell oval, narrowly rounded anteriorly. Beaks prominent. Lunule well 

 marked. The somewhat weathered surface of the shells ornamented by 

 numerous, irregularly-placed growth ridges. Length of type specimen 62 ( ? ) 

 mm., breadth 48 mm. Hinge of right valve with three cardinal teeth and a 

 long, deep tooth-pit for the reception of the anterior lateral tooth of the left 

 valve. Pit between the two anterior cardinal teeth of the right valve ordi- 

 narily narrower and deeper than in C. Newcombei. 



* 



Genus Patella Linnc. 

 Patella geometrica Merriam. 



Plate XXIII, Fig. 4- 



Patelloid, sp. nov., Bull. Dep't Geol., Univ. Cal., Vol. II, No. 3, p. 106. 

 Patella geometrica Merriam, Nautilus, Vol. XI, 1897, p. 65. 



Shell large and heavy, up to 50 mm. or more in length, suborbicular. 

 Apex elevated, well forward. Surface ornamented by about twenty broad, 

 strong, radial ribs, which are much wider than the interspaces. Radial ribs 

 crossed by numerous prominent, narrow, sometimes leafy, transverse ridges. 



