».T« PALEONTOLOGY OF NEW-TORK. 



Daliiiaiiia pleiiroptyx. 



Plate LXXIV. Fio. 1-12; and Plate LXXV. Fio. 1. 



Jliaphua plturoptyz : Grken, Monograph, p. 55, Cast Xo. 18. 



Aaapkus hautmanni, in part of Dk la Heoiik's Catalogue, and of other writers who hare cited this 

 as an American species. 



Head semicircular, with the posterior side concave, and the posterior 

 angles prolonged to the fifth or sixth articulation of the thorax : fron- 

 tal limb slightly concave, thickened at the margin. 



Glabella convex in front ; length from the annulation to the anterior 

 of tl^e frontal lobe, equal to the width of the frontal lobe, which is 

 transversely oval : transverse furrows strongly marked, the anterior 

 one more deeply than the others, and passing imperceptibly into the 

 depression which circumscribes the frontal lobe : anterior lobe ex- 

 panding, and becoming prominent towards the inner angle of the eye ; 

 the central lobe a little wider than the posterior one. Occipital furrow 

 narrow, shallow in the middle ; its continuation in the posterior furrow 

 of the cheeks being yQTy strongly defined, and becoming wider towards 

 the exterior margin. 



Eyes large, prominent, having an elevation of ten ranges of lenses, while 

 laterally there are thirty- seven ranges : the entire number of lenses, 

 in a specimen of medium size, is 311. Between the lenses there is a 

 small round granule marking each of the angles of Or hexagon, which 

 circumscribes the lens. The entire rim of the eye is much elevated 

 above the central portion or palpebral lobe, and a deeper groove in the 

 outer limb. 



Hypostoma subhastate, with scarcely perceptible inequalities on the 

 margin. 



Thorax with the axis somewhat abruptly convex, and about three-fourths 

 as wide as one of the lateral lobes, the articulations on each side ter- 

 minated by a broad node. The articulations of the lateral lobes of the 

 thorax marked by a deep longitudinal furrow, which leaves the elevated 



