352 Annals of thk Carneciie Museum. 



cranidium, bearing no spines, but having a very narrow convex bor- 

 der. Trie anterior border of the cephalon is striate or wrinkled for 

 some distance back from the anterior margin and thickly sprinkled 

 with fine punctae. 



Thorax unknown. 



Pygidiuni. — • Pygidium larger than the cephalon, uniformly convex, 

 the only trace of the axis being on the anterior margin. Surface 

 covered by very fine punctae. 



Measiireiiioits. — A cephalon; length 21 mm.; width 40 mm. 

 Length of furrows, 14 mm., width between posterior ends of furrows 

 18 mm. Width between eyes, 24 mm. 



Cranidium : length 29 mm.; width 36 mm.; furrows 18 mm. long. 



A i)ygidium : length 29 mm.; width 30 mm. 



Another: length 34 mm., width 37 mm. 



Locality. — Type specimens from Smuggler's Bay, Valcour Island. 

 The species is also found at Valcour and Chazy, New York. 



Subgenus Thaleops Conrad. 



Thaleops ovata Conrad. (Plate 13, figure 5.) 



Thalfops 07'ata Conrad, 1843, I'roceedings of the Academy of Natural Science, 



Philadelphia, volume i, page 332. 

 Thaleops {I/hrniis) ovatits Hall, 1847, Paleontology of New York, volume i, page 



259, plate 67, figures 6 a,b. 

 llhenus arcturiis Hall, 1847, Paleontology of New York, volume 1, page 23, plate 



4 bis, figure 12. 

 Ilhemis arctiints Emmons, 1855, American Geology, volume I, part 2, page 235, 



plate 3, figure 12. 

 Illienus clavifrons Billings, 1859, Canadian Naturalist and Geologist, volume IV, 



page 379- 

 Il/itnus aiiturus Billings, 1859, Canadian Naturalist and Geologist, volume IV, 



page 379. 

 IlluiiHS viiidex Billings, 1865, Paleozoic Fossils Canada, volume i, page 179, 



figure 160. 

 Illirnus ovatus Whitfield, 1882, Geology of Wisconsin, volume IV, page 238, plate 



5, figures 1-2. 

 Illccnus herricki Foerste, 1887, 15th Annual Report of the (Jeological and Natural 



History Survey of Minnesota, page 479, figure 2. 

 Thaleops ovatus Clarke, 1897, Paleontology of Minnesota, volume III, part 2, page 



716, figures 25-28. 

 Jllanus ovatus Raymond, I902, Bulletin American Paleontology, volume 3, number 



14. plate 18, figure 9. 



After a careful study of a large amount of material the writer is 



