172 ROYAL SOCIETY OF CANADA 



Agnostus punctuosus, Angelin, var. (PI. I., tig. 3). 



Agnostiis punctuosus, Aug. Palaeontolog. Scand., p. 8, tab. vi., fig. 11. 

 Agnostus pimctuosus, Brog., 1. c, p. 67, tab. vi., fig. 11. 

 Agnostus punctuosus, Tulb., 1. c, p. 17, taf. 1, 13g. 5.f 



Agnostus punctuosus, Faunas of Paradox. Beds of E. N. Am., p. 232, pi. xvi.,^ 

 fig. 11. 



Two undersized individuals (two-thirds of the diameter of the one 

 figured by Tullberg) are indicated ty a pygidium found in one of the 

 limestone bands, and another in the black siliceous shale. This variety 

 differs from the Scandinavian form in the backward projecting spine of 

 the middle lobe of the rachis, in this resembling A. aciileatus, Aug., 

 which has a still longer spine. It also possesses a tubercle on the 

 marginal fold on each side, where a lateral spine is attached in other 

 species ; no such tubercle is figured by Tullberg or Brogger for the 

 Scandinavian form. The pits or tubercles (which are apparently low 

 tubercles with depressed margin) are obscure in the Canadian form. 



Agnostus parvifrons, Linnarsson (PI. I., figs. 4a and b). 



Agnostus parvifroiis, Linrs. Om Vestgot. Camb. o Silur. afiagr., p. 82, tafl. 2, 

 figs. 56, 57. 



Agnostus parvifrons, Brog., 1. c, p. 71, tab. v., figs. 3« to d. 



Agnostus parvifrons, Tullb., 1. c, p. 34, tafi. ii., figs. 26 to 28. 



Agnostus parvifrons, Faunas of Paradox. Beds, p. 220, pi. xvi., figs. 3, a to c. 



An Agnostus which presents the characters of this species is found in 

 the dark siliceous shale. The glabella is somewhat conical and is about 

 half as long as the head-shield, no tubercle was :,observed on this part. 

 The anterior marginal fold is narrow and of comparativelj^ uniform 

 width. 



A pygidium which belongs to an Agnostus of the Parvifrontes section 

 occurs in one of the limestone bands, and may be of this species ; it differs 

 from that of A. umbo mut. (described beloAv) with which it is associated 

 in having a more cyUndrical rachis, and in having the marginal furrow 

 effaced behind. 



The head-shield described above is near the type of the Scandinavian 

 species; it differs ïrom A. parvifrons var. tessella of the horizon Div. 

 Id. 1. of the St. John Basin, in having a rounded front to the glabella, 

 and no trace of a suppressed anterior lobe to the glabella as var. tessella 

 has. 



cf. var. NEPOS Brogger (PI. I., fig. 5). 



cf. parvifrons var nepos Brog., 1. c, p. 72, tab. vi., fig. 2. 



Associated with the above and with A. umbo, mut. (see below) is a 

 pygidium which is nearly of the form of the above variety of A. paroi- 



