no. 1G47. FOSSIL CRABS FROM CALIFORNIA— RATHBUN. 345 



BRANCHIOLAMBRUS ALTUS, new species. 



Plate XLVII, figs. 2 and 3. 



Type.— -Cat. No. 165478, U.S.N.M.; IT. S. Geological Survey Local- 

 ity No. 4859. One specimen. 



This crab is found in a yellow calcareous layer in the gypsiferous 

 shales immediately underlying the Vaqueros (lower Miocene) beds 

 on Wagon Wheel Mountain, southeast quarter, section 36, township 

 25 south, range 18 east, Devils Den District, Kern County, Cali- 

 fornia, about 36 miles southeast of Coalinga. Associated with the 

 crab are Yoldia impressa Conrad, Phacoides acutilineatus Conrad, 

 and an abundant species of Area. The beds are believed to be of 

 lower Miocene age, and closely related to the overlying Vaqueros. 



Carapace about five-sevenths as long as wide, front subtriangular, 

 antero-lateral margin long and arcuate, postero-lateral margin sinu- 

 ous. The widest and highest part of the carapace is at about its 

 posterior third ; from the summit of the branchial region the surface 

 slopes to the margins, the longest incline being toward the front. 



Entire surface covered with sharp granules. Cervical suture shal- 

 low for its anterior two-thirds, becoming deep and narrow posteriorly, 

 where the gastric region is much constricted, ending in an obtuse 

 point. Cardiac region correspondingly narrow, depressed below the 

 branchial level and furnished with two tubercles side by side. At the 

 inner angle of the branchial region and either side of the gastro- 

 cardiac furrow, there is a small but sharp tubercle. 



Frontal teeth three, subequal, broad and blunt, the two outer di- 

 rected a little obliquely, their inner margins having an almost trans- 

 verse direction. The intervals between the tips of the median and 

 lateral teeth are a little less than those between the tips of the lateral 

 and inner orbital teeth, the second sinus being more concave. Orbital 

 tooth acute; width of orbit equal to sinus just in front of it. 



Antero-lateral margin very incomplete; hepatic portion perhaps 

 straight or a little concave ; teeth along the branchial region at least 

 seven, shallow and broad, separated by closed sinuses, tips broken off. 

 A notch just behind the lateral angle forms a small blunt postero- 

 lateral tooth similar to that which occurs so often in the genus Cancer. 

 Postero-lateral margin for most of its length concave, posteriorly 

 convex; margin slightly raised and ornamented with a line of fine 

 granules. The posterior end of the carapace is broken off so that its 

 outline is conjectural. The surface below the postero-lateral margin 

 is steep but not perpendicular, and in a direct view its upper border 

 appears convex (Plate XLVII, fig. 3) ; this surface may represent a 

 distinct facet, as near its anterior end and bounding it below there is a 

 remnant of a horizontal granulated ridge. 



