Katmond. — Isotelus gigas Dekay. 



EXPLANATION OF PLATES. 



PLATE 1. 



Fig. 1. — Isotelus gigas DeKay. An immature specimen with (apparently) 

 three segments in the thorax. From the Trenton at Trenton Falls, 

 N.Y. X 15. No.45, M.C. Z., WalcottcoU. 



Fig. 2. — The same species. A somewhat larger but still immature individual 

 showing the short rounded pygidium of the young. Thorax 

 partially buried in the matrix. From the Trenton at Trenton 

 Falls, N. Y. X 6. No. 48, M. C. Z., Walcott coll. 



Fig. 3. — Isotelus maximus ? Locke. The type of ProUus spurlocki Meek. 

 From the Eden at Cincinnati, Ohio. X 6. No. 43, M. C Z., 

 Dyer coll. 



Fig. 4. — Basilicus barrandi (Hall). A specimen with a narrow brim, similar 

 to the type of Asaphus romingeri Walcott. From the Leray- 

 Black River at Newport, N. Y. X |. No. 46, M. C. Z. Walcott 

 coll. 



Fig. 5. — The same species. A nearly complete but flattened specimen some- 

 what restored about the eyes and at the posterior end of the pygi- 

 dium. From the Black River at the quarry on Limestone Creek, 

 near Platteville, Wise, the type locality of the species, xf - 

 No. 34, M. C. Z., Whitney coll. 



