ASTACIDyE. r,9 



Cat. No. 14G0, Evanston, HI., Prof. 0. Marcy. Mas. Form I. and II. 

 Spec. 2. 



Cat. No. 1820, Ba.«;son Pudge, 111., Mr. Bulten. Mas. Form I. Spec. 1. 



Var. B. Cat. No. 191, Essex, N. J. Fem. Spec. 3. 



Cat. No. 202, New York. Fein. Spec. 1. 



Cat. No. 1821, Beaufort, N. C, Mr. T. Shute. Fem. Spec. 2. 



Dry Spec. Mobile, Ala., L. Agassiz. Male Form I. Spec. 1. 



Peoria, III, Mr. 0. Ordway. Male var. A., Form I. Spec. 2. 



2. Cambarus Clarkii O'hwd. 



Camhanis Clark-ii Girard, Proc. Acad. Pliilad., T. G, p. 91. 



Figmvs on PI. I., II., III., and IV 

 First abdominal leg of tlie male : 



first form, fig. 7 in front ; fig. 8 outside, 

 second form, fig. 9 in front; fig. 10 outside, 

 young, type of C. Clarlii, fig. 99 in front; fig. 100 outside, 

 development of tlie first alidominal leg in tlie young male 0.3 incli long, fig. 133. 



more augmented, to show tlie structure of the knoli, fig. 134. 

 Antennal lamina, fig. 1 37, n ; epistoma, h ; spine of the second joint of the exterior antenna;, c. 

 Tab. IV. mas., first form, New Orleans. 



Mas. Rostro triangulari, lato, dimidio longiori, ante apicem acutum 

 brevem utrinque sinuato vel subdentato, margine vix punctato lineato ; 

 supra la3vi, excavato, basi foveola antice leviter triangulari ; cretis 

 basalibus extus sulcatis, apice extus acutis, fere parallelis, postice 

 tuberculoso couvergentibus. Antennis externis corpore cequalibus, arti- 

 culis duobus basalibus dente externo brevi subacuto ; antennis internis 

 articulo basali dente infero medio acnto ; lamina externa rostro lon- 

 giori, artieulo antennarum tertio tequali, lata, apice rotnndata, margine 

 externo inflato, apice brevi-spinoso. Epistomate brevi, duplo latiori, 

 antice truncato, bisinuato, lateribus oblique productis, subsinuatis. 

 Pedibus maxillaribus externis intus et subtus barbatis. Thorace ntrin- 

 que subcoinpresso, densius tuberculato, cephalothorace supra lani, 

 parce punctato, postice obsolete bicalloso ; linea profunda, modice sul- 

 cata, lateribus fissa, spina infera, ad antennarum basin apicali, acuta ; 

 areola angustissima, medio lineari, profunda, postice dilatata, triangidari, 

 plana. Postabdomine lato, compre.sso, apice subangustiori, la?vi, vix 

 punctato, utrinque obsolete rubro, segmentis penultimis angulo externo 

 postico obtuso ; lamina media parte apicali vix breviori, basi subattenu- 

 ata, apice subsinuata; parte basali apice sinuata, utrinque bispinosa. 

 Pedibus anticis elongatis, longitudine corporis. Chela longa, crassiori, 

 squamoso-tuberculata, margine interno longo, subincurvo, fortiter den- 

 tato ; digitis clielas longitudine, planioribus, apice subdeflexis, subsinua- 

 tis, apicibus acutis, incurvis, la3vibus, intus apice spongiosis, basi siib- 

 dentatis, digito externo tuberculo medio et basali intus majoribus ; 

 digito mobili sublongiori, basi intus exciso. Carpo longo, Itevi, intus 



