THE SPIDER CRABS OF AMERICA 339 



Merus of outer maxillipeds notched at antero-internal angle. Cheli- 

 peds strong; fingers pointed. Ambulatory legs cylindrical; dactyls 

 unarmed. 



Inhabits for the most part Australia, New Zealand and outlying 

 islands. One species only is found in American waters, at Juan 

 Fernandez, Chile. 



PARAMITHRAX BACKSTROMI Baiss 



Plate 123 



Paramithrax -peronii Lenz, Zool. Jahrb., Suppl. 5, 1902, p. 756; not P. peronii 



of Milne Edwards and other authors. 

 Paramithrax hdckstromi Balss, Nat. Hist. Juan Fernandez, vol. 3, 1923, 



p. 336, te.xt-fig. 3 (type-locality, Masatierra, Juan Fernandez). 



Diagnosis. — Near P. peronii Milne Edwards," but with a strong, 

 preorbital spine, only 3 median spines and 3 branchial spines and a 

 rougher cheliped. 



Description. — A small crab. Carapace covered with curled hairs, 

 finely granulate and armed with a few spines; of the median spines 

 2 are mesogastric, 1 intestinal; 2 pairs of submedian spines, 1 pair 

 cardiac, the other on the posterior margin. Supraocular eave pro- 

 vided with a strong anterior and a small posterior spine; this is 

 followed by a longer spine which is half as long as the postorbital 

 spine; the latter has a lobe or tooth on its outer margin and is den- 

 ticulate on inner margin. Two marginal hepatic spines, subequal, 

 directed outward; followed by a small branchial spine, and at the 

 widest part of the carapace by a strong spine; another similar spine 

 above postero-lateral margin. Rostral horns very divergent, acumi- 

 nate. Basal article of antenna with a large, flat, falciform tooth or 

 lobe at outer angle and a small, sharp tooth at inner angle; inner 

 margin denticulate. Fiagellum extending for half its length beyond 

 rostrum. Two sharp spines on the eye, one anterior, on the edge of 

 cornea, the other superior, overlapping cornea. 



Merus of outer maxillipeds subquadrate, with the inner, distal 

 angle deeply notched, a tooth at outer angle of notch; palpus long 

 and stout. ^ 



Merus and carpus of chelipeds ornamented with flat lobes or teeth; 

 about 6 of these form a superior border on the merus; and 5 smaller 

 lobes mark the lower-outer border; inner and outer surfaces unevenly 

 granulate. On the carpus 3 or 4 lobes form a continuous crest 

 above; only 1 lobe below; inner and outer surfaces uneven, the 

 outer having 2 large tubercles. Upper carina of palm sharp, distally 

 wanting. Fingers crenulate within, moderately gaping, no large 

 basal tooth. Ambulatory legs slender, covered with curled hair; 

 distal articulations of merus acute, in first pair spiniform. 



" Hist. Nat. Crust., vol. 1, 1834, p. 324. 



