THE SPIDER CRABS OF AMERICA 357 



PITHO ACULEATA (Gibbes) 



Plate 127; plate 251, fig. 1 



Hyas aculeata Gibbes, Proc. Amer. Assoc. Adv. Sci.. vol. 3, 1850, p. 171 [7] 

 (type-localities, Key West and "Florida"; types not extant). 



Othonia aculeata Stimpson, Ann. Lye. Nat. Hist. N. Y., vol. 7, 1859, p. 49; 

 Bull. Mus. Comp. Zool., vol. 2, 1871, p. 116 (part).— Miers, Journ. Linn. 

 Soc. London, Zool., vol. 14, 1879, p. 673, pi. 13, fig. 6.— Kingsley, Proc. 

 Acad. Nat. Sci. Philadelphia, 1879 (1880), p. 388 (part); not 0. aculeata 

 A. Milne Edwards, Bull. Mus. Comp. Zool., vol. 8, 1880, p. 2.— Rathbun, 

 Proc. U. S. Nat. Mus., vol. 15, 1892, p. 255, pi. .34, figs. 1 and 2. 



Pitho aculeata Rathbun, Ann. Inst. Jamaica, vol. 1, 1897, p. 7; Bull. U. S. 

 Fish Comm., vol. 20, for 1900, part 2, 1901, p. 77. 



Diagnosis. — First movable segment of antenna much wider than 

 long. Lateral teeth of carapace obtuse, the second and third united 

 at base. Fronto -orbital width great. Hands of adult male broad. 



Description. — Carapace a little longer than broad, almost smooth 

 above in adult, more or less tuberculous and granulous in young. 

 Width between outer orbital angles two-thirds of entire uidth. Pre- 

 orbital and external orbital angles subacute. The outer margins of 

 the two external orbital teeth diverge anteriorly. Antero-lateral 

 margins armed with five teeth (exclusive of orbital angle) more or less 

 triangular, obtuse in the old, acute or subacute in the young, the 

 second and third coalesced at their base, the fourth and fifth small. 

 Frontal teeth small, flat, triangular, obtuse. Basal article of anten- 

 nae wide ; that portion of its anterior margin situated outside of the 

 insertion of the next article is denticulate; a deep groove between 

 this crest and frontal border, a second groove on the carapace paral- 

 lel to first. First movable article of antennae Avith an outer lobe 

 much produced laterall}'. 



Chehpeds strong in the full-grown male, about 1.5 times as long as 

 carapace; arm angular, with three depressed tubercles on upper mar- 

 gin; wrist with a smooth longitudinal crest ; palms compressed, about 

 1.5 times as long as wide; fingers widely gaping for their distal two- 

 thirds, with a tooth near the base of the dactyl. Chelipeds in the 

 young male and in the female short and weak; fingers evenly dentate 

 and in contact. The carpus joints of the ambulatory legs have a 

 broad, deep groove on the outer surface. 



Appendages of first segment of abdomen in the male are brown in 

 color for their distal half, the brown parts in contact for half their 

 length, diverging at extremities in slight curves convex to each other, 

 each appendage terminating in a right-angled hook, the point of 

 which is directed toward median line of carapace (fig. 116, c). 



Color. — The following notes on the several lots of specimens ob- 

 tained at Ragged Key were made by Mr. Henderson from the living 

 specimens : 



