ASTACID.E. 73 



excision; the oxamplo is otherwise similar to C.mmunis; nevertheless, 

 it possibly belongs to a dillerent species. 



C. immitnis is a very interesting species; l)y its conical, short, and 



toothless rostrum it is allied to the group of C. Barionii, by the alj- 



dominal legs of the male to the group of C. affiiiis. I have not i-een 



young specimens ; they, perhaps, possess lateral spines. 



'^'Cat. No. 188, Lawn Ridge, 111., Mr. C. Ordway. Male. Fem. Spec. 5. 



^Cat. No. 18-il, Belleville, 111. Male. Spec. 1. 



Cat. No. 301, Huntsville, Ala. Male. Spec. 1. 



Cat. No. 1842, Beaufort, N. C, Mr. Bickmore. Fem. Spec. 1. 



23. Cambarus extraneus Hagen. 



Figures on PI. I. and III. 



First abilominal legs of the male : 



second form, fig. 88 in front ; fig. 89 outside. 



Antennal lamina, fig. 156, a; epistoma, h; spine of the second joint of the exterior an- 

 tenna, c. 



]\Lvs. Rostro lato, duplo vel triplo-longiori, losvi, excavato, margini- 

 bus punctato-lineatis, subparallelis vel subconvergentibus, utrinque ad 

 apicem fortiter sinuatis ; acumine longo, acuto, utrinque dente brevi, 

 acuto ; cretis parum elevatis, parallelis, sulcatis, spina acuta antica. 

 Antennis validis (basis modo exstat), articulis duobus basalibus dente 

 externo acuto, antennis internis articulo basali dente infero acuto ; la- 

 mina rostri longitudine, modice lata, margine externo late inilato, apice 

 spina acuta longiori. Epistomate brevi, lato, antice obtuso, rotundato, 

 angulis lateralibus acutioribus ; pedibus maxillaribus externis intus 

 barbatis. Thorace leviter ovato, densius punctato-ciliato, laterilnis 

 granulosis, scabris ; linea jirofunda, subfissa, ntrinque sjjina valida acuta ; 

 spina antica infera ad antennarum basin ; areola lata, jjlana, punctata, 

 antice posticeque paulo dilatata, cephalothorace margine antico ad basin 

 antennarum loco anguli dente parvo acuto. Postabdomine thoracis lati- 

 tudine, paulo longiori, parce punctato, segmentis antepenultimis angulo 

 laterali subrecto ; lamina intermedia ntrinque bispinosa, parte apicali 

 breviori, rotundata. Pedibus anticis modicis ; chela magna, lata, dejires- 

 sa, densius punctato-ciliata; margine interno longo, subrecto, biseriatim 

 tuberculato-dentato; digitis validis, planis longioribus, costato-lineatis, 

 intus dentatis, basi subtus barbatis. Carpo lato, oblique truncato, parum- 

 punctato, spina interna media majori, aliaque basali brevi; subtus spinis 

 duabus anticis validis. Brachio longiori, la?vi, spinis duabus anteapicali- 

 bus validis, oblique positis, subtus spinis acutis biseriatis, spina ad arti- 

 culationem utrinque valida. Pedibus tertiis articulo tertio unguiculato ; 

 pedibus quartis capitulo basali ovato, parvo. (Forma I. mihi invisa.) 



Forma II. Pedibus abdominalil:)us basi articulatis, validis, brevibus, 

 contortis ; parte interna cylindrica, brevi, apice acutiori recurva ; parte 



10 



