SYNOPSIS OF GENERA. 
xlvii 
than of ProcHus, namely; the glabella is short and ovoid, with large, sub-pyri¬ 
form basal lobes distinctly separated from the body of the glabella, frontal area 
broad and conspicuous. In the type species of Phaeton, however {Pro'etus 
Archiaci and P. striatus, Barrande), the glabella is sub-quadrate or broadly conate, 
the basal lobes not separated from the glabella by the third lateral furrows, 
while the two pairs of anterior furrows are clearly visible. Angelin’s genus 
Phaethonides includes a well-defined group of trilobites allied in certain features 
of the cephalon to Cyphaspis, and in certain features of the pygidium to Pro'etus, 
but it appears very doubtful if this term can be used with propriety to cover 
the species recognized by Barrande under the name Phaeton. Phaethonides 
is represented in the American formations by four species, two from the Lower 
Helderberg and two from the Devonian, and both cephalon and pygidium of 
all these are known. A doubtful species is known from the Devonian rocks 
of Nevada, which seems to be more closely allied to the Pha'eton of Barrande 
than to the Phaethonides of Angelin. Shall it eventually prove necessary 
to separate the species originally included under Pha'eton as generically distinct 
from Phaethonides, recognition should be accorded to the term Prionopeltis, 
Corda, 1847, which name was proposed for the same variations included under 
the term Phaeton, Barrande. 
Genus CYPHASPIS, Burmeister. 1843. 
1843. Cyphaspis, Bukmeistbr. Organ, der Tj-ilobiten. 
1843. Calymene, F. A. RoiMER. Verstein. des Harzgeb. 
1843. Gferastos, Goldfuss. Leonhardt and Bronn’s Neues Jahrb. fiir Min. 
1844. Phacops, C. F. Rcemer. Verstein. d. Rhein. Uebergangsgeb. 
184i). Pro'etus, Lover. Ofversigt. af. Kongl. Vetensk, Akad. Forhandl. 
1846. CyjjJiaspis, Geinitz. Grundr. der Verstein. 
1846. Cyphaspis, Barrande. Notice prdlim. sur. Syst. Silur. 
1847. Cyjyhaspis, CoTwparia, Goniopleiora, Corda. Prodroin Monogr, bdhm. Ti-ilob. 
1850. Cyphaspis, the Brothers Sandberger. Verstein. d. Rhein. Schichtensyst. 
1852. Cyphaspis, Barrande. Syst. Sil. Bohenie, vol. i. 
1852. Cyphaspis, F. A. Ros.mer. Beitr. ii zur Harzgeb. 
1855. CypJiasjns, Shumard. Geol. Surv. Missouri. 
1855. Cyphaspis, F. A. Rcemer. Beitr. iii zur Hai-zgeb. 
1858. Cyphaspis, Giebel. Silui-. Fauna Unterharz. 
1862. Cyphaspis, Hellmann. Die Petrefackten Thiiringens. 
1863. Cyphaspis, Hall. Trans. Albany Institute. 
1869. Cyphaspis, Haidenhain. Zeitschr. der deutsch. geol. Gesellsch. 
1872. Cyphaspis, Barrande. Syst. Sil. Boheme, vol. i, suppl. 
