ASTACIDJ3. 91 



calloso-carinato, marginibus subcallosis 10-dentatis, acumine parvo, acuto, 

 recurvo ; cretis brevibus, impressis, antice subacutis. Antennis modicis 

 (apex deest) ; articulis duobus basalibus dente externo brevi acuto; an- 

 tennis internis articulo basali dente infero anteapicali acuto ; lamina 

 valida trigona, rostri sublongiori, angusta, margine externo sinuato, 

 crasso, apice spina acuta breviori. Epistomate parvo, acute triangulari ; 

 pedibus maxillaribus externis intus barbatis. Thorace ovato, depresso, 

 parce punctato, laeviori ; linea sinuata, modice profunda ; areola lata. 

 Postabdomine thorace non latiori, hevi, segrnentorum angulis externis 

 subacutis; lamina media parte basali quadrangulari apice utrinque bi- 

 spina ; parte apicali breviori, rotundata, margine apicali rotundato in- 

 tegro (mas alter parte basali apice angustiori, utrinque unispinoso ; 

 parte apicali brevi rotundata, margine medio exciso) ; lamina laterali 

 costata. Pedibus anticis validis, longis, spinulosis ; chela magna, elon- 

 gata, subplana, marginibus subacutis, rectis ; supra ad marginem inter- 

 num et externum sulcata ac densius barbata ; digitis validis, rectis, 

 conicis, chela non-longioribus. Carpo lato, truncato, intus scabro ; sub- 

 tus spina media antica parva. Brachio supra ante apicem spinuloso, 

 subtus biseriatim spinuloso, spinis ad articulationem obsoletis. Pedibus 

 abdominalibus brevibus, rectis, dimidio apicali circumvolutis, apice 

 truncatis. 



Long. corp. 3.2"; ped. antic. 3". 



Habitat : California. 



I have seen two males taken by the late Dr. Gambel in California, 

 and communicated by the Academy of Philadelphia ; these same males 

 were examined at an earlier day by Professor L. Agassiz (Proc. Acad. 

 Philad., T. 6, p. 375). 



This species is very remarkable in having tufts of fine erect hair on 

 each side of the hands, giving to the species a very peculiar aspect. 

 The triangular rostrum with dentated margins and the acumen only 

 represented by a similar, but little stronger tooth, instantly separate A. 

 Gambelii from the other Western species. In the second pair of abdom- 

 inal legs the palpus of the penultimate joint is not longer than the leg, 

 though this palpus in A. nigrescens is much longer. 



Mr. Girard, 1. c. p. 91, says : " Anterior pair of abdominal legs elon- 

 gated resembling somewhat in shape those of C. robustus, to which it 

 bears a close relationship." But the type of C. robustus in the Phila- 

 delphia Academy is very near C. Bartonii, while its abdominal legs are 

 very different. Also C. robustus possesses no gills on the fifth pair of 

 legs, and is quite unlike A. Gambelii. 



Of the two males seen by me, one has the intermediate lamina of 

 the postabdomen rounded at the tip, the other strongly and regularly 

 notched. I regard the last as an accidental variety. 



