62 Annals op the Carnegie Museum. 



Section 2. Asaphince with anterior limb of suture intra-marginaj. Pty- 

 chopyge, Pseudasaphus, Asaphus, Onchometopus, Isotelns, Isoteloides. 



Genus Basilicus Salter. 

 This genus includes the most primitive of the Asaphids with f rked 

 hypostomas. The pygidium is strongly annulated, the glabella retains 

 some of the glabellar furrows, the genal angles are spine-bearing, and the 

 facial suture is marginal in front. Many of the species usually referred 

 to Ptychopyge belong to this genus. Only three species are known in 

 America, these being Basilicus marginalis (Hall) of the Chazy, B. romin- 

 geri (Walcott) of the Black River, and B. canadensis (Chapman) of the 

 Utica. As figured, Asaphus canadensis would be a Ptychopyge, but the 

 writer has examined numerous specimens in the Museum of the Geological 

 Survey of Canada without finding a single specimen showing an intra- 

 marginal suture. 



Basilicus marginalis (Hall). 



Plate XVII, figure 6, Plate XIX, figures i, 2. 



Asaphus marginalis Hall, Paleontology New York, I, 1847, 24, pi. 4&?5, fig. 15. 



— Emmons, American Geology, I, ii, 1855, 235, pi. 3, fig. 16. — Raymond, 



Annals Carnegie Museum, III, 1905, 339, pi. 10, figs. 17-20; pi. 11. 



Asaphus alpha Raymond, Annals Carnegie Museum, III, 1905, 342, pi. 12, fig. 9, 



Asaphus gamma Raymond, Annals Carnegie Museum, III, 1905, 342, pi. 12, fig. 10. 



This species is closely allied to Basilicus tyrajinus (Murchison), and 

 the character of the facial suture, the glabellar furrows, and the great 

 number of ribs on the pleura of the pygidium show that it should be 

 referred to Basilicus. 



The shape of the distal end of the pygidium is still in doubt. The 

 accompanying text figure is from a large specimen in the Yale University 

 Museum. The lobes at the side are due to the fracture of the shell, but 

 the posterior lobes, which are not strictly symmetrical with respect to 

 the axis of the pygidium, are natural. 



In the crystalline limestone at McCullough's sugar-bush at Chazy the 

 f ygidia described as Asaphus alpha in my previous paper are quite com- 

 mon, and with them occur cranidia of small size which have the surface 

 marked by very numerous fine granulations. This is the peculiar surface 

 which characterizes Basilicus marginalis, and distinguishes it at once 

 from all the other Asaphids of the Chazy. The cranidia are very small, 

 from 1.5 to 3 mm. in length. The glabella is depressed convex, definitely 

 outlined, with three pairs of shallow glabellar furrows. In front of the 

 glabella there is a wide flattened border which is crossed by a narrow ridge, 



