90 BULLETIN 138, UNITED STATES NATIONAL MUSEUM 



nearly straight, armed with strong teeth, the median one forming a 

 small rostrum; lateral borders curving regularly inward; hind 

 margin very narrow. 



Cretaceous; Eocene; Oligocene; Miocene; Pliocene; Recent. 



Both species here described fall into Fabiani's division Etero- 

 ranina^^ otherwise typical Ranwa. 



RANINA TEJONIANA, new species 



Plate 22, figs. 1 and 2 



Descriptian.—Csiraijace (pi. 22, fig. 1) very convex from side to 

 side, nearly flat from front to back. Sides of carapace as preserved 

 very arcuate, armed with two depressed spines the origins of which 

 are to be seen on the left side. The posterior of the spines, at the 



FIG. 1. R'ANINA TEJONIANA. STERNUM (FIRST SEGMENT AND BPISTERNUM) OF HOLOTYPB, 



X 3 



antero-lateral angle, is smaller than the other; its cross-section is a 

 little more than twice as long as wide, the cross-section of the larger 

 is three times as long as wide, and the distance between them is equal 

 to the length of the smaller cross-section. The longitudinal distance 

 of the posterior end of the base of the posterior spine from the outer 

 orbital angle is greater than the transverse distance of that angle 

 from the line of the greatest width of the carapace. Only two or- 

 bital teeth, the two outermost, are visible; both are truncate, sepa- 

 rated by an open suture, inclined a little inward; outer margin of 

 outer tooth very oblique and slightly convex, a point at its outer 

 corner has been broken off. Similar spines may have been present 

 at the corners of the second tooth. 



Very little of the true outer surface of the carapace remains; a 

 small piece near the anterior middle is smooth, while another piece 



^ Boll. Mus. Civ. Vicenza, vol. 1, 1910, p. 31 ; Atti Accad. Sci. Veneto-Tieutlno- 

 Istriana, ser. 3, anno 3, Padova, 1910, p. 88. 





