ASTACIDJE. 39 



Cat. No. 1460, Evanston, EL, 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, III, 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., ami IV 

 First abdominal leg of the male : 



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

 second form, fig. 9 in front; fig. 10 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. Rostro triangularis lato, dimidio longiori, ante apicem acutum 

 brevem utrinque sinuato vel subdentato, margine vix punctate lineato ; 

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

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

 tubei*culoso convergentibus. Antennis externis corpore aaqualibus, arti- 

 culis duobus basalibus dente externo brevi subacute ; antennis internis 

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

 giori, articulo antennarum tertio requali, lata, apice rotundata, margine 

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

 antice truncato, bisinuato, lateribus oblique productis, subsinuatis. 

 Pedibua maxillaribus externis intus et subtus barbatis. Thorace utrin- 

 que subcoinpresso, densius tuberculato, cephalothorace supra loevi, 

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

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

 areola angustissinia, medio lineari, profunda, postice dilatata, triangulari, 

 plana. Postabdomine lato, compresso, apice subangustiori, laevi, vix 

 punctato, utrinque obsolete rubro, segment is 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 interim longo, subincurvo, fortiter den- 

 tate ; digitis chelae longitudine, planioribus, apice subderlexis, subsinua- 

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

 dentatis, digito externo tuberculo medio et basali intus majorilms; 

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



