CRUSTACEA. 131 



border. It bears about twelve transverse annulations. The lateral slopes are 

 gentle and bear nine or ten flattened annulations, each of which appears to 

 be faintly sulcate. Surface minutely granulose. The larger of the two speci- 

 mens measures 18 mm. in length ami 23 mm. in width : the smaller 14 mm. in 

 length and IS mm. in width. This species has proportions similar to those of 

 Pro tits macrocephalus, but has fewer annulations and lacks the conspicuous 

 ornamentation of that species. It is not closely comparable with anv >>{' the 

 species here described. 



Distribution. Hamilton group. New Buffalo, Iowa. 



Proktus(?) longicaudus. 



TLATE XX, FIGS. 32-34. 



Proetus longicaudus, Hall. Fifteenth Rept N. Y. State Cab. Nat. Hist., p. 108, pi. x. figs. 7 '.'. 1862. 

 Pnul'is longicaudus, Hall. Illustrations of Devonian Fossils, pi. xx. figs. 32-34. l^T'i. 

 Proetus longicaudus, H. S. Williams. Amer. Journ. Science, vol. xxi, 3d Ser., p. 156. 1881. 



General Form and Proportions. Body elongate-ovate, tapering, with margins 

 rounding to the posterior extremity. 



Cephalon broadly semi-elliptical, transversely very convex. Border wide and 

 thick, produced into short spines at the genal angles. 



Glabella sub-ovoid, slightly constricted opposite the anterior angles of the 

 eyes, and somewhat abruptly rounded in front. First lateral furrows faint 

 and very short ; second and third pairs gently curving backward, extending 

 nearly two-thirds the distance across the glabella; fourth pair of furrows 

 conspicuous, passing from near the middle of the palpebral lobe to the 

 occipital furrow, and forming two large sub-pyriform basal lobes, each of 

 which reaches about one-third the distance across the base of the glabella. 

 Occipital lobes wanting ; occipital ring broad and flattened above, becoming 

 narrower on the cheeks. 



Cheeks broadly marginate. 



Eyes sub-reniform, moderately large and closely appressed upon the glabella. 



Thorax composed of nine segments. 



