CONTRIBUTIONS TO PALEONTOLOGY. 103 



thickened border. About half the ribs are distinctly divided to- 

 wards their extremities, and a faint groove is perceptible along 

 the whole length of several of the anterior ones. The crust is all 

 preserved except on the greater part of the glabella, and though 

 somewhat worn ( from much handling ), appears to have been 

 finely granulose or papillose, the worn surfaces a little punctate. 

 The edges of the border, both of head and pygidium, are striate. 



This neat and beautiful species was presented to me many years since by 

 Professor S. S. Haldeman, of Columbus, Pa. The specimen is from Penn- 

 sylvania, probably from rocks of the age of the Hamilton group. At this 

 time I have before me the pygidia of several specimens from the Goniatite 

 limestone, near the base of the Hamilton group, which are specifically un- 

 distinguishable from this one ; having the same number of ribs and propor- 

 tions essentially the same, not differing more from the typical form than 

 may result from pressure and other causes. The surface of one specimen is 

 somewhat rougher ; and in one, the groove of the ribs is more strongly 

 marked. 



In the body and head, this species is readily distinguished from the others 

 here described : in the separated pygidia, the axis is less prominent and 

 more pointed below. 



Geological formation and locality. In limestone of the age of the Ha- 

 milton group? Pennsylvania ; and in the Goniatite limestone, Manlius and 

 Cherry-valley, N.Y 



PROETUS ROWI. 



alymene rowi : Green, Anier. Journal of Science and Arts, Vol,xxxiii, p. 406. 



This Trilobite was first noticed by Mr. Le How, in the Poughkeepsie 

 Telegraph, Nov. 22, 1837; and described by Prof. Green in the following 

 year, as cited. Several years since, I obtained the loan of the original spe- 

 cimen from Mr. Le Row, and had a cast taken in plaster, and a drawing 

 made : the plaster cast measures a little more than one inch and a half. I 

 have a mould in stone of a specimen from Otsego county, which measures 

 nearly the same as the former. 



The entire head is ovate ; the breadth at base of buckler is one inch, 

 and, at the anterior margin of the pygidium, three-fourths of an inch. The 

 head and body are remarkably convex ; the glabella-extremity prominent, 

 ovate ; the length half an inch, and the greatest width between the eyes a 

 little more than four-fifths of an inch, somewhat contracted just opposite the 

 anterior angles of the eyes. The glabella-furrows are indistinctly shown in 

 the mould in stone, and in another imperfect specimen ; and the posterior 

 one has apparently produced a slight indentation at the base. The eyes are 

 very prominent, and much below the plane of the summit of the glabella. 

 1861.] 



