284 bulletin: museum of comparative zoology. 



In Newfoundland Schuchert and Twenhofel found this species in 

 zones M2, Ni, and the Isolated limestone, all at Table Head. These 

 specimens differ from the ones described above in having the crani- 

 diuni a little shorter and broader, the posterior part of the glabella 

 a little wider, and a slightly shorter axial lobe on the pygidium. 

 Specimens nearer these than the other Virginian specimens were 

 collected bv Dr. Shuler on the northern side of Walker Mountain 

 near White Gate, Bland Co., Va. 



This species is much more nearly related to Bronteopsis ardmilla- 

 7iensis Reed, than to the type of the genus. The Scottish species has 

 a slightly different conformation of the fixed cheeks and more traces 

 of ribs on the pleural lobes of the pygidium, but the differences between 

 the two species are small. B. nitens Wlman, obtained from boulders 

 of the older Chasmops limestone, has a somewhat wider glabella 

 and a more acutely triangular axial lobe on the pygidium than our 

 species. Cotypes M. C. Z. 1,595 to 1,597. 



AsAPHiDAE Burmeister. 



NiLEOiDEs, gen. nov. 



Some years ago I described (Annals Carnegie museum, 1910, 3, 

 no. 1, p. 69, pi. 18, fig. 7, 8. Seventh rept. Vermont state geologist, 

 1910, p. 224, pi. 38, fig. 7, 8. Trans. Roy. soc. Canada, 1912, ser. 3, 5, 

 sect. 4, p. 119, pi. 2, fig. 8, pi. 3, fig. 1) N ileus perkinsi found in the 

 Upper Chazy on Isle La Motte, Vt. While evidently closely allied 

 to Nileus, this species differs from all other species of that genus in 

 having the eyes relatively small and particularly in having them very 

 far back. Another peculiarity is the strong development of the verti- 

 cal suture on the doublure. I have examined with care great num- 

 bers of specimens of Nileus from Norway and Sweden without ever 

 finding this suture, nor does it show in any of the American speci- 

 mens. The strong development in Nileoidcs perkinsi is therefore of 

 considerable importance. 



Cephalon Nileus-like, glabella not outlined, cranidium smooth, gently 

 convex, elongate, not abruptly inflected in front of the eyes. Eyes large, 

 but not so large in proportion to the length of the cephalon as in Nileus. 

 Vertical suture present. Axial lobe of thorax wide. 



Type, Nileus perkinsi Raymond. Upper Chazy, Vermont. 



