771 



Proe. 



has a narrower middle lobe, -| instead of } Ihe whole length of 

 the animal, and few segments in the side lobes, with a flattened 

 instead of thickened border; surface as far as seen smooth, and 

 coincides with all the markings of the cast, showing that the 

 skin of the trilobite was like thin horn. VIII a. 



Proetus protuberans, Hall, Pal. 3. VI 



Proetus prouti, Shumard, 1863. VIII c. 



Proetus rowi. ( Calymene rowvL Green, Am. J. S. XXX III, 



NyvoilviLpi 



1838, p. 4G6.) Hall, Desc. New Sp. 1861 ; 15th An. Rt. N. Y. St. 

 Cab., 1862, p. 103; HI. Dev. Foss. 1876, 21, 2-6; Pal. N. Y. 

 Vol. 7, 1888, page 119, plate 21, figs. 2 to 6, 24 to 26 (all 

 omitted) ; plate 23, selected fig. 20, a large entire individual; 

 23, young, with very large eyes; 24, still younger; 25, a small 

 one with two of his chest segments jammed up under his head- 

 piece; 26, two lying together with average size; 27, natural 

 size; 28, a small one preserving part of the shell. These are 

 from Erie, Ontario and Seneca Cos., N. Y. The head is cov- 

 ered with faint tubercles. It is one of the rarer species of 

 Hamilton age; only found abundant and in good condition at 

 one place, on Leaver's creek, Canandaigua township, Ontario 

 Co., N. Y., in the shales and limestone just over the dark Mav- 

 celliis shales. It is so like P. claries., Hall, of the Upper Ilel- 

 derherg^ as to be its descendant, but it has larger eyes and a 

 peculiar marking of its own. — Hamilton. VIII c. 



