Ravmond-Narraway : Notes on Ordovician Trilohitks. 49 



free cluvks ratluT small, ihr part i)rli>\v the t'\c ht'iiig sUiddcd with sharp 

 tubercles. The ijcnal antijlcs are pnuliurd into long spines. 



The in'gidiuni is shorter than that of Bathyiirns extans, and the axial 

 lobe even more iirominent. There are four pairs of strongly marked ribs 

 on the i)leural lobes, all but the last pair showing an impressed median 

 line. The axial lobe shows two distinct rings and from one to three in- 

 distinct ones, the smaller specimens showing the more rings. The first 

 two rings bear median and lateral tubercles, and from tlu' third and toiirlh 

 rises a large spine which tapers rapidly and is curved backward. Hack 

 of this spine the axial lobe is nearly smooth, there being no strong rings, 

 but there are usualK' a munber of small tubercles arranged in rows parallel 



to the axis. 



Family ASAPHID.E Emmrich. 



Gemis Basilicus Salter. 



Basilicus romingeri (Walcott). 



Plate XV, figures 9-10; Plate XVI, figures 1-4. 



Asaphus romingeri Walcott, Twenty-eighth Annual Report New York State 



Museum, 1879, 96. 

 Asaphus wisconsensis Walcott, ibidem, 1879, 97. 



Ptychopyge romingeri Clarke, Paleontology Minnesota, III, ii, 1897, 709. 

 Ptychopyge ulrichi Clarke, ibidem, 1897, 709, figs. 12, 13. 



This species is fairly common in the Black River at Ottawa, though no 

 complete specimens have been found. The facial suture proves to be 

 marginal in front, and therefore this species belongs to Basilicus and not 

 to Ptychopyge. 



Fig. I. Basilicus lyrannus (Murchison). Outline drawing to show course of 

 facial suture. After Salter. 



Fig. 2. Ptychopyge anguslifrons (Dalman). Outline drawing to show facial 

 suture. After Brogger. 



