58 Annals of the Carnegie Museum. 



4. Bathyiirns spiniger (Hall). Dorsal view of a free cheek from the Black 

 River limestone at Mechanicsville, near Ottawa, Ontario. Nearly twice natural 

 size. Specimen in the Carnegie Museum. 



5. The same specimen; side view. 



6. The same species. Side view of a well preserved pygidium from the same 

 locality as the last. From Mr. Narraway's collection. 



7. Bathyiirns extans (Hall). A large specimen in the Carnegie Museum from 

 the Lowville at Black River, New York. About natural size. 



8. The same species. An hypostoma from the Lowville at Mechanicsville, 

 Ontario. About natural size. In Mr. Narraway's collection. Collected by Mr. 

 J. S. Hale. 



9. Basilictts romitigeri (Walcott). A small pygidium from the Black River at 

 Mechanicsville. The specimen is in Mr. Narraway's collection, and the figure is 

 about natural size. 



10. The same species. A specimen from the Black River at Poland, New York. 

 This specimen shows parts of seven segments of the thorax, the hypostoma, and 

 parts of the free cheek and pygidium. It is in the Museum of Cornell University, 

 and the figure is about natural size. 



Plate XVI. 



1. Basilicus romingeri (Walcott). An incomplete free cheek from Faribault, 

 Minn., now in the Carnegie Museum. The shell is exfoliated from the portion in 

 front of the eye, and the anterior limb of the facial suture shows as a line on the 

 inner surface of the doublure. Natural size. 



2. The same species. A cranidium from the Black River at Mechanicsville, 

 Ontario. Twice natural size. In the collection of the Carnegie Museum. 



3. The same species. A cranidium from Faribault, Minnesota. Specimen 

 in the Carnegie Museum. Natural size. 



4. The same species. A small specimen from Faribault, Minnesota. This 

 specimen shows a low axial ridge in front of the glabella such as is seen in speci. 

 mens of Basilicus marginalis of all sizes. Twice natural size. 



5. Bathyurus extans (Hall). A hypostoma from the Lowville limestone at 

 Mechanicsville, Ontario. Twice natural size. Specimen in the Carnegie Museum. 



6. Onchometopus simplex Raymond and Narraway. An imperfect cranidium 

 from Faribault, Minnesota. Natural size. Specimen in the Carnegie Museum. 



7. The same species. A pygidium from the same locality as the last. Natural 

 size. 



8. The same species. An incomplete specimen in the Carnegie Museum from 

 Franklin Forge, Pennsylvania. Natural size. 



9. Isoteloides homalnotoides (Walcott). A pygidium from the Black River 

 limestone at Pattersonville, New York. A little less than natural size. Specimen 

 in the Carnegie Museum. 



10. The same species. A cephalon drawn from a nearly complete specimen 

 from the same locality as the last. 



11. The same species. An exfoliated cranidium from the lower part of the 

 Trenton at Smith's Basin, New York. Notice the small eyes and the two shallow 

 pits which are vestiges of glabellar furrows. Natural size. Specimen in the Car- 

 negie Museum. 



