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Transactions of the 



Linn." They resemble as much the trilobite as cancer, 

 perhaps they will prove to be an intermediate genus. 

 Locality. Little Falls, New York. 



ORDER BRANCHIOPODA. 

 Genus Eurypterus. Dekay. 

 E. remipes. J. E. Dekay, 



Annals of the Lyceum of Nat. Hist. vol. i. p. 375. pi. 29. 



Character of the genus. " Caput a thorace non dis- 

 tinctum : os ignotum : oculi duo, sessiles, distantes, lu- 

 nati : abdomen elongatum, posticam versus extremita- 

 tem sensim gracilius, segmentis trans versis subimbrica- 

 tis di visum. Pedes octo ; duo utrinque antici branchi- 

 feri, duo utrinque postici maximi, omnes lamellosi." 



Description. " Head roundish, marked anteriorly 

 by a deep indented line formed by the junction of the 

 superior and inferior plates. Eyes distinctly lunated, 

 much depressed, and marked by concentric striae ; feet 

 four pair ; the two anterior composed of four or more 

 nearly equal articulations, of which the terminal one is 

 the smallest and bluntly pointed, furnished with filaments, 

 which from their size &c. are supposed to be branchiae ; 

 the third pair are rather longer than the two preceding, 

 and entirely destitute of filaments. The fourth or pos- 

 terior pair are placed near the junction of the head 

 with the abdomen, and are larger in proportion to the 

 body than in any living genus of Crustacea. As nearly 

 as can be determined from the faint and broken impres- 



