[MATTHEW] STUDIES ON CAMBRIAN FAUNAS 89 



5. — Dwarf species with large glabella, and apical spine to the front 

 margin, suture within the rim. Cainatops. Upper Paradoxides 

 Beds. 

 C. pustulosus, Matt.' 



ATOPS, sub-gen. 



as a genus by Emmons, 1844. 



Atops trilineatus, Emmons, (PI. lY., fig. 8.) 



Atops trilineatus, Emmons, Taconic Syst., p. 20, fig. 1, pi. ii, fig. 3. 



Calymene Beckii, Hall, 1847, Pal. N. Y., vol. 1, p. 252, pi. Ixvii., figs. 4a-e. 



Atops trilineatus, Haldeman, 1848, Am. Jour. Sci., 2nd Ser., vol. v., p. 107. 



Atops punctatxis, Emmons, 1859, Manual of Geol., p. 88, fig. 71. 



Atops trilineatus, Barrande, 1861, Bull. Soc. Geol. de France, 2nd Ser., t. xviii., p. 



269, pi. v., fig. 1. 

 Atops punctaius, Barr. 1861, Ibid, p. 271, pi. v., fig. 3. 



Conocephalus (Atops) trilineatus. Ford, 1871, Am. Jour. Sci., 3rd Ser., vol. ii., p. 33. 

 Conocephalltes trilineatus. Ford, 1873, Ibid, 3rd Ser., vol. vi., p. 13.5. 

 Triarthrus trilineatus. Miller, 1877, Cat. Am. Pal. Foss., p. 223. 

 Calymene Beckii, Wale, 1879, Trans. Alb. Inst., vol. x., p. 23. 

 Conocoryphe, Ford, 1880, Am. Jour. Sci., 3rd Ser., vol. xix., p. 153. 

 Ptychoparia trilineata, Walcott, 1886, U.S. Geol. Surv. Bull. 30, p. 203, pi. xxvii., 



figs. 1, la-c, 

 Conocoryphe trilineata, Walcott, 1887, Am. Jour. Sci., vol. xxxiv., p. 187, figs. 7, 76. 



The above record will show how this species has been bandied about 

 from one genus to another, until it has found a resting place in Cono- 

 coryphe. Whether it shall remain there or not, only the future can tell, 

 but Atops has a strong claim. It was S. W. Ford who first appreciated 

 its relation to the European genus Conocoryphe. 



Through the favour of Mr. J. P. Howley, the author has received an 

 example of the above species, obtained from the shales at Manuel's Brook. 

 As it shows some features of the species that have not been described it 

 is noticed in the following paragraphs. 



It may be premised that the fossil is a cast of the interior surface, 

 and shows the cephalic shield and ten joints of the thorax. The fossil is 

 flattened and slightly distorted. 



For a better understanding of the points at issue, Emmons's description 

 of the species is quoted. " Crust granulated, cephalic shield semicircular 

 with its anterior and lateral edges turned upwards ; posterior angles 

 rounded, facial suture beginning at the outer angle of the cephalic shield 

 and runs nearly parallel with the anterior margin to the middle lobe, 

 when it turns at a right angle and runs parallel with that lobe ; eyes 

 undistinguishablc, body composed of seventeen or eighteen rings, narrow- 

 ing very gradually to the caudal extremity ; pygidium a flat expansion 



1 Trans. Roy. Soc. Can., 2nd Ser., vol. iii., sec. iv., p. 174, pi. i., fig. 8. 



