CRUSTACEA. 255 



relations whicli may exist between the marine and fresh water representati-wes of this inter- 

 esting genus. 



To facilitate their researches, I subjoin the references I have gathered touching the history of 

 the two species described by diiferent authors. 



iEGLEA L^VIS, Leach. 



Stn. Galathealcevis, Latr. Encycl. Meth. Crust. PI. cccviii, iig. 2. 

 ^glea Icevis, Leach, Diet. Sc. Nat. XVIII, 1820, 49. 



Desm. Consid, Gen. Crust. 1825, 186, PI. xxxiii, fig. 2. 



Latr. in Guv. Eegn. Anim. IV, (2d edit.) 1829, 84. 



Grief. Guv. Anim. Kingd. XIII, 1833, 184, PL yii, fig. 2. 



MiLN. Edw. Hist. Nat. Cr. II, 1837, 258 ; Atlas du Kegn. Anim. de Cuvier, PL 



xlvii, fig. 3. 

 Edw. et Luc. in D'Orh. Voy. Amer. Merid. VI, I. Crust. 1843, 34. 

 Nio. in Gay, Hist, de Chile, Zool. Ill, 1849, 199. 

 Dana, U. S. Expl. Exped. Crust. XIII, I, 1852, 4T6, PL xxx, fig. 6. 



iEaLEA DENTICULATA, Nic. 

 Syn. JEglea denticulata, Nic. in Gay, Hist, de Chile, Zool. Ill, 1849^ 200, Lam. ii, fig 1. 



iEGLEA INTERMEDIA, Girard. 



StEC. CHAR. Carapax finely punctate ; rostrum moderate, acute, depressed (incurved) upon its 

 middle, with its point slightly turned upwards. Edges of carapax subdenticulated ; denticula- 

 tions more conspicuous on the stomacal region than on the branchial region. Anterior legs 

 larger in the male than in the female ; in both sexes the arm has a prismatic shape, and is 

 denticulated upon its upper and its lower and inner edges ; the external lower edge being nearly 

 smooth. Carpus provided with two rows of subconical tubercles (teeth) upon its upper and 

 inner portion. Hand exhibiting internally a flattened processus, often denticulated. Inner 

 edge of claws tuberculous or sub tuberculous. Abdominal segments divided into three lobes, by 

 an undulating line forming a subaneate triangle upon each segment. 



Desc. The body is very much depressed, longer than broad ; anteriorly about half the width 

 of the posterior margin. The depth upon the middle region is about equal to the width of the 

 anterior region immediately behind the orbits. The margin of the carapax is sharp and slightly 

 indentated; the outline is slightly incurvated upon the suture which separates the thoracic from 

 the cephalic region. The latter, convex upon its middle, is terminated anteriorly by a subtri- 

 angular, acerated, and carinated rostrum, slightly raised upwards upon its tip. On each side 

 of the rostrum a semi-elliptical notch, at the external angle of which a small spine exists, con- 

 stitutes the orbit. The suture, between the cephalic and thoracic regions, is very convex pos- 

 teriorly upon the middle region, then slightly concave laterally and anteriorly, then again 

 oblique towards the edge of the carapax. 



The thoracic region is divided by two longitudinally shallow and smooth furrows into three 

 regions — a medial or cardial, and two lateral or branchial regions. Again, it divides trans- 

 versally into three regions also — an anterior, a medial, and a posterior ; the last embracing a 

 very narrow space upon the posterior extremity of the carapax, and extending but very slightly 

 upon the branchial regions. The central portion of the cardial region is slightly convex, and 

 limited by a sinuating depression or groove. The last segment of the thoracic region is move- 



