CRUSTACEA. 
13 
the outline and contour usual in this part of Bronteus. It may, therefore, 
with propriety, be regarded as belonging to this species. 
Observations. This species is represented only by the two fragments 
described, both of which were discovered by Professor S. G. Williams, of Cor¬ 
nell University, by whose kindness this notice appears. ' Unusual interest 
attaches to it as the first representative of the genus Bronteus discovered in 
the Devonian of America, although the genus is abundantly represented in 
the Devonian horizons of Europe. A close relationship is observable in the 
species Brojiteus Tullius and B. granulatus, Goldfuss, from the middle Devonian 
of the Eifel and the lower upper-Devonian limestone of the Iberg-Winterberg 
terrane. This similarity consists in the number and contour of the ribs and the 
ornamentation of the dorsal surface and doublure. The fauna of the I berg lime¬ 
stone is characterized by a very abundant development of the species Rhyn- 
chonella cuboides, Sowerby, of which species the American representative R. 
venustula, Hall, occurs only in the Tully limestone, the formation from which 
Bronteus Tullius has been derived. The row of minute spinules along the pos¬ 
terior margin of the pygidium of our species shows its relationship to the 
comparatively limited group of forms following the type of Bronteus thijsanopeltis, 
Barrande. This group includes at present the following species, viz.; B. thysa- 
nopeltis, Barrande, B. clementinus, Barrande, B. acanthopeltis, Schnur, B. Barrandii, 
Hebert, B. Waldschmidti, von Koenen, B. Raphaeli and B. Trutati, Barrois, 
and B. Tullius. In Bronteus Tullius these spines are much more minute than in 
any other of the species mentioned. Kayser^ has observed that this group of 
Bronteus stands in the same relation to the Silurian forms of the genus as the 
genus Criyphoeus does to the normal forms of Dalmanites, i.e., those after the 
type of D. Hausmanni. So far as known, it is limited to Devonian faunas, and 
is appropriately designated by the term Thysanopeltis, applied to this variation 
by Corda (Prodrom. Monog. Trilob., 1847), and revived by Barrois (Ann. de la 
Soc. Geol. du Nord, p. 131, 1886), with sub-generic value. 
Distribution. Hamilton group. In the Tully limestone, Kingsley’s Hill, north¬ 
east of Otisco, and Borodino, Onondaga county. 
* Jilteste Devon-Ablag-. des Hai’zes, p. 255. 1878. 
