THE SPIDER CRABS OF AMERICA 295 



hepatic region; oblique ridge separating pterygostomian from sub- 

 hepatic region armed with five spines, the anterior three small and 

 toothlike. Horns rather large and divergent, forming more than 

 half length of rostrum, their tips as well as those of the antennal 

 spines bent inward. All of the spines are much more acute in young 

 specimens than in adults. 



Chelipeds long, merus armed with numerous (about 13) blunt 

 spines on outer side; carpus tuberculated above; hand large, com- 

 pressed, perfectly smooth and unarmed above and below; fingers less 

 than half as long as palm, and gaping; the dactylus bears a strong 

 truncated tooth at middle. Merus of ambulatory legs armed with 

 7 to 10 spines along the upper edge, and two or three below near the 

 extremity; carpus slightly tuberculated, propodus unarmed. 



Adult males entirely naked, young and females frequently pubes- 

 cent. (After Stimpson.) 



The supraorbital border bears two small teeth, of which the outer 

 is the larger. Basal antennal article armed with three spines on 

 the orbital border, counting the antero-external spine. Carpus of 

 cheliped smooth. (A. Milne Edwards.) 



Notes on cotype from AcapvJco.— The specimen is now in poor con- 

 dition. Of the five antero-lateral marginal spines, the single hepatic 

 spine is the largest. The nine postero-lateral spines or spinules are 

 very small. Of the dorsal branchial spines three form an arc parallel 

 to the outer margin and are stouter and more conical than any other 

 branchial spines. The penult segment of the male abdomen is widest 

 near its distal end. 



Color. — A light flesh tint (Lockington, as armatus). In spirits 

 bright red, manus, under sides of legs and buccal apparatus especially 

 bright (Lockington, as depressa). 



Measurements. — Length of carapace of adult male, type, 17.1 mm. 

 (.675 inch), width 14.4 mm. (.57 inch) (Stimpson). Female, Mazat- 

 lan, length of carapace 32 mm., width 30 mm. (Lockington, as 

 Mithrax armatusT). 



Range. — Cape St. Lucas to Acapulco, Mexico (Stimpson). Maz- 

 atlan (Lockington, as armatus). Port Escondido and San Jose Is- 

 land, Gulf of California (Lockington, as depressa). Patos Island, in 

 upper half of Gulf. 



Holmes" extends the range of this smooth-handed species into 

 California; but all the Calif ornian specimens examined by the writer 

 7.5 mm. long and over show spines or spinules on the proximal 

 upper margin of the palm and should be referred to the following 

 species. 



Material examined. — Acapulco, Mexico; A. Agassiz, collector; one 

 male (991, M. C. Z.); labeled by Stimpson " Herhstia parvifrons," 



" Occas. Papers California Acad. Sci., vol. 7, 1900, p. 37. 



