ASTACID^. 35 



1. Cambarus acutus Girard. 



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



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



First abdominal legs of the male : 



first form, fig. 1 in front; fig. 2 outside; fig. 108 outside viewed more laterally; fig. 10G 



inside, 

 second form, fig. 4 in front ; fig. 3 tip augmented ; fig. 5 outside, 

 fig. 110 outside, young, 1.7 inch long; fig. Ill outside, 2.7 inches long, 

 fig. 112 outside, 2.7 inches long, not articulated ; fig. 113 outside, 1.4 inch long, not articu- 

 lated, 

 var. A, first form, fig 107 inside; fig. 109 outside. 

 Venter between the fourth pair of legs of the female, fig. 114, C. acutus ; fig. 115, var. A. 

 Rostrum, fig. 116, C. acutus; fig. 117, var. A. 

 Epistoma, fig. 118, C. acutus ; fig. 119, var. A. 

 Thoracic line, fig. 1 24, C. acutus ; fig. 1 25, var. A. 

 Inner sexual parts of the male : 



first form, fig. 120; testicles viewed from above, fig. 121. 

 second form, fig. 122. 

 Inner sexual parts of the female, fig. 1 23. 

 Annulus ventralis of the female, fig. 126 outside; fig. 127 inside. 



Antennal lamina, fig. 143, a ; epistoma, b ; spine of the second joint of the exterior antennae, c ; 

 fig. 144, the same parts for var. B, from New Jersey. 



Mas. Rostro triangulari, lato, dimidio longiori, subdeflexo, ante api- 

 cem brevem acutum utrinque subsinuato, margine punctato-lineato ; 

 supra lasvi, subexcavato, basi late foveolato ; cretis basalibus extus 

 sulcatis, apice subacutis, fere parallelis, postice callosis convergentibus. 

 Antennis externis corpore oequalibus vel longioribus, articulis duobus 

 basalibus dente externo brevi, subacute) ; antennis internis articulo 

 basali ante medium dente infero, acute* ; lamina externa rostro longiori, 

 antennarum peclunculo cequali, lata, apice rotundata ; margine externo 

 inflato, apice brevi-spinoso. Epistomate brevi lato, excavato, antice 

 rotunclato. Pedibus maxillaribus externis intus et subtus barbatis. 

 Thorace postice latiori, densius taberculato ; ceplialothorace supra fere 

 loevi, parce-punctato, postice obsolete bicalloso ; linea profunda, sinuata, 

 lateribus clivisa, spina infera ad antennarum basin apicali, modica ; 

 areola angusta, carinata, postice latiori, plana, interdum transverso- 

 impressa ; margine postico subexciso. Postabdomine lato, apicem ver- 

 sus subangustiori, loevi, parce-punctato, segmentis utrinque macula 

 obsoleta rubra ; segmentis penultimis angulo externo postico recto ; 

 lamina media parte apicali breviori, apice rotundata, margine medio 

 exciso ; parte basali apice utrinque bispina. Pedibus anticis valde 

 elongatis, corpore interdum longioribus ; chela longa, angusta, modice 

 tumida, squamoso-tuberculata ; margine interno longo, subrecto, forti- 

 ter dentato ; digitis longioribus, interno sublongiori, supra planis, sub- 

 tus medio elevatis ; externo recto, interno sinuato ; digitis basi tubercu- 

 latis, externo tuberculo medio et basali interno ; interno basi intus 

 exciso, margine externo basi tuberculato. Carpo longo, latere interno 



