40 ASTACID^. 



tuberculato, spina media majori ; subtus spinis duabus majoribus anticis, 

 aliisque minoribus intemis. Brachio rostro longiori, extus laevi, intus 

 ante apicem et margine supero tuberculato, spinis duabus anteapicali- 

 bus oblique positis; subtus biseriatim spinoso, spinis internis apicali- 

 bus validis. Pedibus tertiis et quartis articulo tertio unguiculato ; 

 pedibus quartis et quintis capitulo basali, quartis oblongo-ovali, 

 quintis compresso, laminato. 



Pedibus abdominalibus brevibus, rectis, cylindricis, basi et ante 

 apicem attenuatis, vix bifidis ; parte externa margine postico dente 

 medio obtuso, apice dentibus brevibus duabus compressis, corneis, latis, 

 rotundato-incurvis ; parte interna apice spina fusiformi, acuta. 



Forma II. differt antennis chelisque brevioribus, unguiculis pedum 

 minoribus; pedibus abdominalibus basi articulatis, minus attenuatis, 

 parte externa apice fere obtuso, bituberculato, dentibus obscurioribus, 

 nee fusco-corneis ; parte interna spina conica breviori. 



Mares formse secundae variant bracliio rostro breviori, lateribus 

 cephalothoracis minus tuberculatis ; spina laterali ad lineam transversam 

 (semper fere nulla in Forma I.) ; forma et latitudine rostri et acuminis 

 variabili, vel marginibus rectis, vel subrotundatis ; acumine basi dis- 

 tinctius dentato. 



Femina differt antennis chelisque brevioribus, minoribus, minus tuber- 

 culatis; ventre inter pedes quartos nudo, non tuberculato; annulo ovali, 

 obtuse conico, fissura longitudinali, labiis antice inflatis, sulcatis, fere 

 bituberculatis. 



Long. 3 and 4 unc. Mas maximus; long. 4.2; ped. ant. 4.7 ; antenn. 

 4.5 ; chelae, 2.6. 



Patria : New Orleans. Between San Antonio, Texas, and El Paso 

 del Norte. Vidi specimina multa, adulta et juniora. 



This species is very similar to C. acutus, but it differs surely; the 

 rostrum is more evidently dentated before the acumen, and the obso- 

 lete impression at its base is terminated anteriorly by two oblique 

 elevated lines ; the epistoma is truncated and sinuated anteriorly and 

 laterally; the thorax is laterally compressed, the areola linear in the 

 middle ; the penultimate segments of the postabdomen with the ex- 

 terior angle are more obtuse; the apical part of the intermediate 

 lamina is as long as the basal, a little attenuated at the base ; the 

 chelae are shorter and broader ; the legs of the postabdomen different ; 

 the venter of the fourth legs in the female is without tubercles. 

 There is rarely one spine at the sides of the thorax. 



C. Glarldl Grirard. I have most carefully compared male and female 

 types collected by the U. S. Mexican Boundary Commission, communi- 

 cated by Professor Stimpson. They belong, without doubt, to this 

 species. The male is a young specimen of the Forma II. (1.8 unc. 



