DESCRIPTION OF A NEW SPECIES OF CRAB FROM THE 

 CALIFORNIA PLIOCENE. 



By Mary J. Rathbun, 



Associate in Zoology, United States National Museum. 



The specimen here described was given to the United States Na- 

 tional Mupeum by Mr. J. Z. Gilbert, of Los Angeles, California, who 

 obtained it from the foundation of one of the large buildings in that 

 city. Mr. Gilbert states that it was associated with a large number 

 of marine shells embedded in blue clay; that it is the same formation 

 as outcrops on the south side of the Hill Street hills at Fourth Street 

 and Broadway; and that the formation hes unconformably under the 

 fresh-water gravel, sand, and bowlders, and at an angle of about 35°. 



CANCER URBANUS, new species. 



Plate 59. 



Type-locality. — Los Angeles, Cahfomia; from foundation of large 

 building; PHocene period; J. Z. Gilbert, collector and donor; 1914. 



Holoiype.—C&t. No. 324300, U.S.N.M. A single specimen em- 

 bedded in blue clay. Only the carapace remains and that is imper- 

 fect, especially as to the margins. Carapace narrow, actual width 

 44 mm., measured between antero-lateral sinuses; estimated width 

 at the same place, 48 mm.; length, about 34 mm. There are two 

 diagonal breaks on the left side of the carapace with corresponding 

 faults; the width of the right half is therefore more nearly normal. 

 The surface is about equally convex from side to side and from front 

 to back. The interregional depressions are deep; surface uneven, 

 closely granulate, the granules larger and more prominent on the most 

 elevated portions. (See pi. 59.) Antero-lateral teeth 9, includ- 

 ing the tooth at the lateral angle of the carapace and at the outer 

 angle of the orbit; teeth acute, their margins straight, anterior mar- 

 gin usually considerably shorter than posterior margin; margins of 

 seventh or widest tooth nearly equal. Edge of front and orbit broken 

 away, but the furrows which lead back from the sinuses of the anterior 

 margin are deep. 



Proceedings U. S. National Museum, Vol. 53-No. 2214. 



451 



