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 and 23 mm. in width; the smaller 14 mm. in 
length and 18 mm. in width. This species has proportions similar to those of 
ProHus macrocephalus, but has fewer annulations and lacks the conspicuous 
ornamentation of that species. It is not closely comparable with any of the 
species here described. 
Distribution. Hamilton group. New Buffalo, Iowa. 
PrOETUS (?) LONGICAUDUS. 
PLATE XX, FIGS. 32-34. 
Proetus lovgicaudns, Hall. Fifteenth Rept N. Y. State Cab. Nat. Hist., p. 108, pi. x, figs. 7-9. 1862. 
Proetus lojigicaudus. Hall. Illustrations of Devonian Fossils, pi. xx, figs. 32-34. 1876. 
Proetus longicaudus, H. S. Williams. Ainer. 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. 
