40 ASTACID.E. 



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

 aliisque minoribus internis. Brachio rostro longiori, extus la?vi, intiis 

 ante apicem et margine supero tuberculato, spinis duabus anteapicali- 

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

 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 attenuates, vix bifidis ; parte externa margine postico dente 

 medio obtuso, apice dentibus brevil)us duabus compressis, cornels, latis, 

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



Forma II. difFert antennis clielisque brevioribus, imguiculis 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 formfc secundte variant brachio rostro breviori, lateriljus 

 ceplialothoracis minus tuberculatis ; spina laterali ad lineam transversam 

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

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

 tinctius dentato. 



Femina differt antennis clielisque brevioribus, minoriljus, minus tuber- 

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

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

 bitul)erculatis. 



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

 4.5 ; chelaj, 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. acidm, but it differs surely ; the 

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

 lete impression at its base is tei'minated 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 postabdomeu 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 

 chela3 are shorter and broader ; the legs of the postabdomeu 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. Clai'Jdi Gii'ard. I have most carefully compared male and female 

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

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

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



