88 
PALEONTOLOGY OF NEW YORK. 
Observations. The genus Dicranogmus was established by Corda {loc. cit.) for 
a form of Lichas, in which the longitudinal furrows of the glabella become 
obsolete before reaching the anterior margin. It is stated by Barrande (Syst. 
Sil. du centre de la Boheme, vol. i, pp. 43, 609), that the group was founded 
upon a single very fragmentary specimen, and it has not been accorded recog¬ 
nition by him for the reason that “ le prolongement plus ou moins grand des 
sillons de la glabelle est un caractere tres-variable dans divers types ” (p, 609). 
It is nevertheless true that very few species of the genus Lidias bear longitu¬ 
dinal furrows which become anteriorly obsolete at so great a distance from the 
frontal margin as in the species L. pustulaius, Corda, which served as the type 
of Dicranogmus; and it may be questioned whether in any species of Lichas, 
except those following the type of Dicranogmus, the anterior longitudinal 
furrows become obsolete before reaching the margin. No evidence of this fact 
is shown in the species described by Barrande, Angelin, Dames and Schmidt, 
and none is found in any other American species of Lichas. The species Lichas 
gibbus, Angelin, Lichas simplex, Barrande ( = Dicranogmus pustulatus, Corda), and 
Lichas ptyonurus have in common the characteristic obsolescence of the anterior 
longitudinal furrows and serve to form a distinct subdivision of the genus. 
Distribution. Niagara group. Coralline limestone: Schoharie, Schoharie 
county. 
