360 ALLAN* HANCOCK PACIFIC EXPEDITIONS VOL.21 



Remarks: The decision to combine material collected by Agassiz and 

 Orcutt and described by Rathbun as Mithrax (Mithrax) orcutti with 

 the specimen collected much earlier by Verreaux and described by Saus- 

 sure as Mithrax armatus results from a growing conviction that there is 

 but one large intertidal Mithrax species on the west coast of Mexico and 

 Central America. This species has now been taken three times at Maz- 

 atlan : by A. Agassiz and the writer, in addition to Verreaux. Its range 

 has been extended northward to Los Frailes by the Vetera IV and south- 

 ward to Corinto by the Zaca. 



Rathbun (1925, p. 399) knew her species to be very near to Mithrax 

 armatus. but could not reconcile it with the entirely smooth palm and 

 the greater carapace width opposite the third, rather than the fourth, 

 lateral spine in Saussure's species. In a female the size of Saussure's type 

 (1}$ French inches) the tubercle on the outer surface of the manus 

 would be an insignificant feature ; its position even in large males is such 

 as to leave the major portion of the surface of the manus unbroken. 

 With respect to the apparent greater width anteriorward, this might be 

 a matter of parallax, since the spines are at a higher level than the swollen 

 lateral margin ; in any event, too much reliance should not be placed 

 upon the accuracy of the scientific art of this period (1853). 



Mithrax (Mithrax) sinensis* Rathbun 

 Plate V, Fig. 5; Plate 41, Fig. 1 



Mithrax sinensis Rathbun, 1892, p. 266, pi. 38, fig. 2; 1898, p. 579; 



1923b, p. 635. 

 Mithrax (Mithrax) sinensis, Rathbun. 1925, p. 419, pi. 151, figs. 3, 4; 

 pi. 260. Crane, 1937, p. 60. Garth, 1948, p. 29. 



Type: Male holotype, U.S.X.M. No. 16065, length 9.2 mm, width 

 8.9 mm. 



Type locality: Off San Jose Island, Gulf of California, Mexico, 17 

 fathoms, Albatross station 3002. 



Localities subsequently reported, ivith collectors: Gulf of California, 

 Mexico: San Esteban Island, Albatross (Rathbun, 1923b); off Santa 

 Cruz and off Cerralvo Island, 7-10 fathoms, Albatross (Rathbun, 

 1898) ; Gorda Banks, 20-30 fathoms, Zaca (Crane). Colombia: Hum- 



*The species name is derived from "sinus" a gulf or bay, not "Sina," China 

 according to Rathbun (1898, p. 579, footnote). 



