54 BULLETIN 138, UNITED STATES NATIONAL MUSEUM 



type & can be made out except that the abdomen is narrow and the 

 sternum smalL 



Measuretnents. — Holotype, width of carapace 43.6 mm., fronto- 

 orbital width 23.3 mm., posterior wudth 11.5 mm., chord of antero- 

 lateral margin 18.5 mm., postero-lateral margin 23.2 mm. 



Occurrence. — Oregon : 1 mile south of Henderson Station 

 (Springfield Junction), Southern Pacific Railroad, Lane County; 

 200 or 300 feet above the other specimens; Oligocene series; one 

 specimen of carapace with front and left antero-hi teral margin broken 

 away, holotype; Cat. No. 353373, U.S.N.M. 



California: Llajas Canyon, Simi Valley; Santa Susana Shales, 

 the basal member of the Meganos Group (according to Dr. Bruce L. 

 Clark) ; middle Eocene ; two specimens, one of which is a male, para- 

 tyi^es. 



Relations. — This species can not be confused with the much more 

 abundant Z. vulgaris.^ because of the different areolation of the cara- 

 pace. In vulgaris the posterior branchial region is covered with a 

 large swelling instead of two small separated bosses, the epibran- 

 chial region has a long obliquel}^ transverse areole instead of a small 

 round one, the cardiac region has two areoles side by side instead of 

 one median, the hepatic region is convex instead of flat, the mesogas- 

 tric region is plainly divided from the protogastric. 



Z. hendersonianus is, however, very closely allied to Z. dufourii 

 (Milne Edwards), ^^ from the Eocene of Europe, and yet appears 

 to be specifically distinct. Some of the dorsal bosses are of differ- 

 ent cliaracter : In dufourii the metabranchial boss is round instead 

 of elongate, the cardiac boss round and circumscribed instead of 

 embracing the Avhole region, the intestinal boss also round instead 

 of oblong. The tooth at the superior inner angle of the orbit is j 

 directed forward or nearly so, instead of obliquely outward with an i 

 almost transverse inner margin, as in hendersonianus. The lateral 

 lobes are larger and more prominent. 



Z. hendersonianus has also much in common with Zanthoysis' 

 gruentensis (Schafhiiutl),^^ but in that species the tooth at the lateral • 

 angle of the carapace is in a transverse line with the anterior of the ' 

 metabranchial lobes and the median gastric lobes are broad and par- 

 tially subdivided by a longitudinal furrow. 



ZANTHOPSIS STERNBERGI, new species 



Plate 39 



Description of holotype. — A right cheliped in a curved position. 

 Merus, carpus and manus very wide (or high) in proportion to 



i«A. Milne Edwards, Ann. Sci. Nat., ger. 4, Zool., vol. 20, 1863. p. 309, pi. 6. 

 '■' Siid-Bayerns Lethaea Geognostica, Leipzig, 1863, p. 228, pi. 61, flg. 4 a-c. 



