386 The Ohio Journal of Science [Vol. XIX, No. 7, 



Bumastus cf. ioxus (Hall). 

 Plate XVI, Fig. 5. 



Illaemis ioxus Hall, 20th Rent. New York State Cab. Nat. Hist., 1868, p. 378, 



plate 22, figs. 4-11. plate 23, fig. 1. 

 Illaemis ioxus Weller, Bull. Chicago acad. sci.. 1907, no. 4, pt. 2, p. 222, pi. IS, 



figs. 1-3. 

 Bumastus ioxus Raymond, Bull. Mus. Comp. Zool. Harvard Coll., vol. 60, no. 1, 



1916, p. 20'. 



Bumastus ioxus was described from the Racine dolomite; 

 it is known to occur both at Joliet, Illinois and at Racine, 

 Wisconsin. 



At the Whitfieldella cylindrica horizon, nine feet above the 

 base of the Lower or Bisher member of the West Union forma- 

 tion, at the exposures along the hill-front northeast of the 

 Bisher dam bridge, about a mile southeast of Hillsboro, Ohio, 

 a large cranidium of Bumastus was found, which evidently is 

 closely similar to that of Bumastus ioxus. 



In this specimen from the West Union formation the palpebral 

 lobes are relatively smaller and the distance from these lobes to the 

 anterior margin of the cephalon is relatively greater. The facial 

 suture intersects this margin where the latter has not curved as strongly 

 backward as in typical Bumastus ioxus. Dorsal furrows faint, broad, 

 and shallow, confined to the area opposite the palpebral lobes. The 

 convexity of the cranidium is only moderate. 



Closely similar large cranidia occur in the Osgood limestone, 

 in the vicinity of Osgood and elsewhere in Ripley county, 

 Indiana. 



Proetus undulostriatus Hall. 

 Plate XIX, Figs. 6. 12. 



The type of Proetus undulostriatus was refigured by Ruede- 

 mann in Bulletin 162 of the New York State Museum, in 1912. 

 In this figure (Loc. cit., pi. 9, fig. 2) only the right posterior 

 lobe appears to be differentiated on the glabella. In a second 

 specimen figured in the same bulletin from the same locality 

 and horizon (Loc. cit., pi. 9, fig. 3) three pairs of glabellar 

 furrows are indicated. Of this second specimen Dr. Ruede- 

 mann prepared for me an outline drawing (PI. XIX, Fig. 12) 

 accompanied by the description given below. In view of the 

 great difficulty of distinguishing species of Proetus from differ- 

 ent Ordovician horizons, these notes by Dr. Ruedemann will 

 prove very useful. Both specimens of Proetus undulostriatus 



