SPIDER CRABS.- -RATHBUN. 13 



by a cluster of three tubercles, forming a line which is con- 

 tinued on the pterygostomian region by three or four tubercles. 

 The antero-lateral angle of the buccal cavity is produced' 

 downward in a rounded lobe. 



The narrow basal joint of the antenna has a shallow furrow 

 through the middle, and a small forward-pointing tooth at 

 the outer angle ; the first movable joint is very short, the 

 next two are long, the remainder of the rlagellum does not 

 reach the tip of the rostral horn. 



Fig. 3. Antilibinia lappacea, Ratitlmn, 

 right chela of female holotvpe. six and two- 

 thirds times natural size. 



The cheliped of the female is shorter and stouter than the 

 first ambulatory leg ; the arm has a stout terminal spine 

 above and a few tubercles near the proximal end. The 

 wrist has an upper crest which is produced in a squarish 

 lobe near the proximal end. Legs rather slender, diminishing 

 in size from the first to the fourth pair, the HHTUS joints 

 each terminating in a superior tooth. 



Fifth and sixth segments of female abdomen fused, although 

 a suture line is faintly visible. 



Relationships. The genus Antilibiiia already contains tun 

 species, viz., the type, A. xmitln'i MacLeay 15 from Natal, and 

 A. gilloloensis Rathbun 16 from the Molucca islands. A. 

 smithii has an uneven, somewhat lumpy surface, t.wo lateral 

 teeth or spines, one hepatic, one branchial, a rostrum cut 

 only half way to its base, a moderate preocular and post/ocular 

 spine and rounded joints of chelipeds and legs. A . gilloloensis 

 has also an uneven surface, but less lumpy than smithii, no 

 tooth or spine on the margin of the branchial region, hut a 

 small one on the hepatic region, a rostrum and preocular 

 and postocular spines similar to those of ^4. smithii, but a 

 carinated wrist and arm. A. lappacea, while having the 

 antennal and orbital characters possessed by the other 

 species, has a more smoothly rounded carapace, the cardiac 

 region alone appearing as a separate area ; the branchial 

 spine or tooth is missing, as in .4. gilloloensis, but the hepatic 

 spine is elongated and conspicuous ; the rostral horns are 



- . / r 



15. In Smith Illus. Zool. 8. Africa, Aimulosa, 1838, p. f>7. pi. ii 



16. Rathbun Proe. U.S. Nat, Mus., 1.. 116, p. .537. 



