Boone, Crustacea, Cruises of "Eagle" and "Ara," 1921-28 97 



states that there are three inferior and lateral and three spines on 

 the superior orbital margin in addition to the pre- and postorbital 

 and antennal spines. Miss Rathbun states that one of her specimens 

 has four spines here. The anterolateral margin is armed with four 

 major spines, the first of which, occupying the entire hepatic margin, 

 is trifid, consisting of a long, curved spine with a smaller acute one on 

 either side of it; the second, third and fourth major spines are each 

 bifid, consisting of a long spine with its tip curved forward and an- 

 teriorly an acute spine which is only from one-half to two-thirds as 

 long as the major spine; the fourth spine is at the lateral angle; pos- 

 terior to this and distinctly higher upon the carapace is a single, 

 shorter, postlateral spine. The lateral walls of the carapace are 

 armed with a series of smaller spines. 



The chelipeds are subequal ; when extended those of the young male 

 reach only a slight distance beyond the tips of the rostrum ; the merus 

 is armed with five longitudinal rows of spines, of which the upper two 

 are longest; the carpus is small and very spinous; the propodus is 

 elongate, with two broken rows of spines on the upper surface; the 

 fingers have the tips spoon-shaped, with the edges crenulate. 



The ambulatories each have the merus armed on the upper surface 

 with two rows of long spines and two of short spines; the carpus is 

 spinose; the propodus is elongate, subcylindrical, roughened with 

 nodules, produced at its union with the dactyl into a strong, knob- 

 like protrusion which reinforces the joint ; the dactyl is long, slender, 

 with a slightly curved, very acuminate tip, and bears numerous long, 

 stiff setae. 



Synonymy. — Cangrejo espinosa Parra, Descripcion de diferentes 

 piezas de historia natural, p. 127, pi. 47, fig. 1, 1787. 



Mithrax cornutus Saussure, Rev. et Mag. ZooL, ser. 2, vol. 9, p. 501, 

 1857; Mem. Soc. Phys. Geneve, vol. 14, p. 423, 1858.— A. Milne 

 Edwards, Crust. Reg. Mex., p. 97, pi. 22, fig. — , 1875.— Miers, 

 Challenger Rept. Zool., vol. 17, pp. 86, 87, 1886. — Verrill, Trans. 

 Conn. Arts and Sci., vol. 13, p. 400, 1908.— Rathbun, Bull 129, 

 U. S. N. M., p. 386, pi. 137, figs. 3 and 4, pi. 256, 1925. 



Mithrax (Mithrax) holderl Stimpson. 



Plate 29, fig. B. 



Diagnostic characters : Carapace pyrif orm, definitely longer than 

 wide ; deep cervical-urogastric groove ; surface broken by many areolae 

 and tubercles ; postlateral spine, also hepatic spine well defined. 



