ASTACIDiE. 39 



Cat. No. 1460, Evanston, HI., Prof. 0. Marcy. Mas. Form I. and II. 

 Spec. 2. 



Cat. No. 1820, Basson Pudge, 111., Mr. Bulten. Mas. Form I. Spec. 1. 



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



Cat. No. 292, New York. Fern. Spec. 1. 



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



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



Peoria, 111., Mr. 0. Ordway. Male var. A., Form I. Spec. 2. 



2. Cambarus Clarkii Girard. 



Cambarus Clarkii Girard, Proc. Acad. Philad., T. 6, p. 91. 



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



First abdominal leg of the male : 



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



second form, fig. 9 in front ; fig. 1 outside. 



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

 development of the first abdominal leg in the young male 0.3 inch long, fig. 133. 



more augmented, to show the structure of the knob, fig 134. 

 Antennal lamina, fig. 137, a ; epistoma, b ; spine of the second joint of the exterior antenna?, c. 

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



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

 brevem utrinque sinuato vel subdentato, margine vix punctato lineato ; 

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

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

 tuberculoso convergentibus. Antennis externis corpore sequalibus, arti- 

 culis cluobus basalibus dente externo brevi subacute ; antennis internis 

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

 giori, articulo antennarum tertio aequali, lata, apice rotundata, 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 utrin- 

 que subcompresso, densius tuberculato, cephalothorace supra lsevi, 

 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, triangulari, 

 plana, Postabdomine lato, compresso, apice subangustiori, lsevi, 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, longitucline corporis. Chela longa, crassiori, 

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

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

 tis, apicibus acutis, incurvis, laevibus, intus apice spongiosis, basi sub- 

 dentatis, cligito externo tuberculo medio et basali intus majoribus; 

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



