90 North American 



PHILI^IPSIA DOKIS, Hall. 



Praetuii Doris, Hall, Contributions to Palaeontology, 1858-59, p. 57. 

 Proetus Doris, Hall, 1860, 13tli Rep. X. Y. State Cab. Xat. Hist., p. 112. 

 Phillipsia Doris, Winchdl, 1865, Proc. Acad. Xat. Sci. Pliila., Vol. IX, 



p. 133. 

 Phillipsia Doris, Herrick, 1887, Bull. Sci. Lab. Denison Univ., II, p. 62. 



AVe subjoin the original description of this species drawn by Prof. James 

 Hall from the pygidiuni : 



'"Caudal shield .semi-elliptical, convex; the axis gibbous, rounded and 

 very prominent in old specimens, obtuse posteriorly. The plane border of 

 the pygidium is about half as wide as the lateral lobe, and defined by a 

 shallow depression on the inner side, marked by about 8 ribs, while the axis 

 is marked by 13 or 14 in full grown specimens. Surface granulous." 



Qeological formation and locality. — Goniatite limestone at Rockford, In. 

 diana. 



Prof. Alexander W'incbel], in the Proceedings of the Acad. 

 X^at. Sci. Philadelphia, for 1865, ]). 133, remarks: 



" This species was established by Hall on some ]iYgidia occur- 

 ing in the Goniatite limestone at Eockfoi'd, Indiana. I am in 

 possession of several pygidia from this locality which ngrce with 

 his description, though in the absence of meastirements, it may 

 be that his specimens are mnch larger. Associated with these are 

 nnmerons fi-agments of bucklers, which prove that the trilobite 

 is a Pliillipna. The head is furnished with a border sloping 

 downwards, and separated from the cheeks by a deep but narrow 

 groove; the middle of the border is marked by a groove which 

 reaches from a point opposite one eye, to the corresponding 

 point on the other side of the head ; in some specimens the latter 

 groove reaches backward to the posterior borders of the buckler ; 

 the cheeks are raised abruptly above the border, and terminated 

 by spinous points which are ornamented with raised longitudinal 

 striae, and extend backwards a distance equal to one-third the 

 whole length of the cephalic shield. The principal lobe of the 

 glabella is in the form of a prolate semi-ellipsoid, is almost desti- 

 tute of furrows, and is stipported on each side by a large com- 

 plementary lobe. The surface is obscurely granulose. The py- 

 gidium is in form of a semi-ellipse, with the longer diameter 

 transverse ; it is convex, with a gibbous axis, obtuse posteriorly, 

 and articulated to the extremity. The lateral lobes are a little 



