262 CALIFORNIA ACADEMY OF SCIENCES. 



ACIDASPIS. AGNOSTUS. 



TUBERCULATUS Hall, 1859; Pal. New York, vol. 3, p. 368, pi. 79, figs. 



1-14. Albany and Schoharie counties, N. Y. 



TUBERCULATUS Hall, 1861; 15th Kep. New York State Cab. Nat. His., 



pi. 2, fig. 3. 



Ceratocephala (Acidaspis) TUBERCULATUS Clarke, 1892. Note 011 Aci- 

 daspis, p. 13. 



AGLASPIS Hall, 1862; Canadian Naturalist, vol. 7, p. 445, figure. Hall, 

 1863; 16th Eep. New York State Cab. Nat. Hist., p. 181. 



- BARRANDI Hall, 1863; 16th Kep. New York State Cab. Nat Hist., p. 



181, pi. 11, figs. 7-16. Miniska, Minn., and Mazomaiiia, Wis. 



Taconic. 



- EATONI Whit., 1880; Ann. Rep. Geol. Survey, Wisconsin, p. 52. 



- EATONI Whit., 1882; Geol. Wisconsin, vol. 4, p. 192, pi. 10, fig. 11. 



Lodi, Wis. Taconic. 



Arctinurm De Castelnau, 1843; Sil. Syst. de 1'Amerique, p. 21. (See 



Lichas boltoni.) 



AGNOSTUS Brong., 1822; Hist. Nat. Crust. Foss., p. 38. Taconic. Cambrian. 

 Syn., Battus Dalm., 1826; Palaead., p. 33. 



Trinodus McCoy, 1846; Sil. Foss. Ireland, p. 56. 

 Phalacroma Cord, (in part), 1847; Prodr., p. 158. 

 Mesospheniscus Cord., 1847; Prodr., p. 46 (Agnostus integer). 

 Diplorrhina Cord., 1847; Prodr., p. 46. 

 Condylopyge Cord., 1847; Prodr., p. 50 (Agnostus rex}. 

 Lejopijge Cord., 1847; Prodr., p. 51 (Agnostus laivigatus). 

 Arthrorhachis Cord., 1847; Prodr., p. 114 (Agnostus tardus). 

 Peronopsis Cord., 1847; Prodr., p. 115 (Agnostus integer). 

 PleurocteniumCord., 1847; Prodr., p. 116 (Agnostus granulatus) . 

 Sec. 1. PARVIFRONTES. The glabella is only partly developed in this 



section. Type Agnostus brevifrons Ang. 



Sec. II. LOXGIFRONTES. This section is distinguished by its strongly 

 projecting glabella and also by the axis of the pygidium, which is 

 generally moderately long. Crust smooth. The cheeks grooved. 

 The crust on the cheeks and pygidium is provided with raised 

 points. Limb generally narrow. The cheeks in front of the glabella 

 and side lobes of the pygidium, behind the axis, divided by a 

 groove. Type Agnostus punctuosus Ang., A. pistformis Linne. 

 Sec. III. LIMBATI. General form subquadrate, head has a broad limb, 

 basal lobes large. The cheeks in front of the glabella are not 

 divided by a central groove or grooved at the sides. The pygidium 

 is usually produced into lateral spines. Type Agnostus rex Barr. 

 Series A (REGII). Distinguished by its broad limb, diminishing cheeks 

 and side lobes of the pygidium. Both the anterior lobe of the 

 glabella and the posterior lobe of the pygidium expand. Type 

 Agnostus rex Barr. 



