8 PROCEEDINGS OE THE NATIOITAL MUSEUM tol. 78 



from the lower Oligocene (?) of Biarritz, but the arrangement of 

 the tubercles is different — the cardiac region has 2 median tubercles 

 in one cluster instead of a single centred tubercle, and the inner part 

 of the branchial region is isolated and its pattern consists of a clus- 

 ter in which one tubercle is surrounded by 6 or 7 ; in our species the 

 branchial region is not subdivided, nor a group of tubercles isolated. 

 Both species have a small tooth at postero-lateral angle. A com- 

 parison of figures ^"^ shows a striking difference in the proportions 

 of the carapace, verrucosa longer than broad, hondoensis broader 

 than long. However, the author's illustration of verrucosa^" does 

 not correspond with the statement of measurement, width 9 mm., 

 length 8; a proportionate length for our incomplete type-specimen 

 would be 16.6, which is reasonable and in conformity with the posi- 

 tion of the orbital angle. 



Family RANINIDAE 



RANINA (?), species 



Plate 6, Figure 2 



Description. — A fragment of an appendage resembles somewhat 

 the left wrist or carpus of a Raninid. It shows the greater part of 

 the outer surface and part of the upper surface; the narrow end 

 (at the left in the figure) represents the distal articulation with 

 the manus; the adjacent concave margin borders the manus; the 

 article is very thick, but the inner surface is lacking. The outer 

 surface is rough with granules of varying size, toward the lower 

 edge becoming very fine and then disappearing. On the upper 

 surface which curves over inward, granules are few and scattered; 

 7 in all and 2 tubercles. The greatest length of the fragment is 

 19.8 mm. 



Occurrence. — ^Lower California : In Arroyo Hondo, 1 km. above 

 junction with Arroyo Conejo; upper sandstone of Tepetate forma- 

 tion, upper Eocene; December 2, 1920; Coll. No. 9695. 



Although it is impossible to place this specimen definitely, its 

 shape and ornamentation will permit future identification. 



KANINOroES MEXICANUS, new species 



Plate 4, Figure 1 



Description. — The exact position of this species is problematic. 

 The general form of the carapace behind the spine on the anterior 

 portion of the side margin is urn-shaped; spine directed forward 

 and slightly outward; a broad rounded sinus within or anterior to 



"A. Milne Edwards, C. R. trav. Congr&s Sci. France, session 39, Pan, 1873, pi. 4, fig. 3. 



