288 BULLETIN 152, UNITED STATES NATIONAL MUSEUM 



circular, with two suture lines above and one below; inner-lower 

 tooth not prominent. Antennae as in Xaniho. Anterior edge of 

 merus of external maxillipeds very oblique. Chelipeds unequal in 

 both sexes, strong. Legs thick. Abdomen of male with its seven 

 segments distinct. 



Contains only one species. 



HOMALASPIS PLANA (Milne Edwards) 



Plates 128-130 



Xantho planus Milne Edwards, Hist. Nat. Crust., vol. 1, 1834, p. 397 (type- 

 locality, Chile; type in Paris Mus.). — Milne Edwards and Lucas, d'Or- 

 bigny's Voy. I'Amcr. M6rid., vol. 6, pt. 1, 1844, p. 14; atlas, vol. 9, 1847, 

 pi. 6. — NicoLET, in Gay, Hist. Chile, vol. 3, 1849, p. 136. — Porter, Revista 

 Chilena Hist. Nat., vol. 9, 1905, p. 31, pi. 3. 



Gecarcinus regius Poeppig, Arch. f. Naturg., vol. 2, pt. 1, 1836, p. 136 (type- 

 locality, Chile; type in Leipzig Mus.). — Nicolet, in Gay, Hist, Chile, vol. 

 3, 1849, p. 153. 



Homalaspis planus A. Milne Edwards, Ann. Sci. Nat., ser. 4, vol. 20, 1863, p. 

 280. 



Xantho plana Philippi, ZooI. Anz., vol. 17, 1894, p. 265[2]. 



Diagnosis. — Margin of carapace obscurely lobed. Front extremely 

 narrow, fused with orbital margin. Of large size. 



Description. — Surface covered with coarse depressed crowded gran- 

 ules most evident aroimd the antero-lateral arch. Mesogastric region 

 faintly outlined. Antero-lateral margin thick, divided by three 

 closed fissures or thumb-nail impressions into four lobes; the first 

 two lobes follow the general outline of the carapace, with but a slight 

 shallow emargination between, second lobe longer than first; the third 

 lobe projects a little, the fourth still more; from the fourth a ridge, 

 concave forward, curves obliquely inward and backward. Anterior 

 margin of front bilobed, lobes oblique, their margins concave, sepa- 

 rated by a small V-shaped median emargination which is continued 

 back for a short distance by a closed fissure. Sides of front forming 

 with inner margin of orbit a very oblique line. Superior orbital fis- 

 sures obscure, not interrupting the curve of the margin; no tooth 

 at outer angle; two well-developed teeth below, the one at inner 

 angle larger than the other. The inclined front is produced consider- 

 ably beyond the peduncle of the antennae. Outer maxillipeds coarsely 

 granulate, especially so on the merus and distal end of the ischium; 

 merus widest at its middle, bearing two deep depressions, hairy in 

 the old. 



Chelipeds massive; the merus is almost entirely covered by the 

 carapace and has a subterminal tooth above, formed by a deep tri- 

 angular indentation. Inner angle of carpus dentiform, very blunt. 

 Fingers strong^ toothed, teeth mostly white, a large backward- 

 pointing tooth at base of major dactylus. The dactyli of the am- 



