1896. ] NEW YORK ACADEMY OF SCIENCES. 227 
reason for this since we have discovered that the pygidium re- 
ferred provisionally to one of these forms (A. partitus) is of a 
different type from the usual pygidium of a Longifrontes, and 
therefore should be referred elsewhere; we have consequently 
included under this species, A. partitus and A. acutilobus. 
Var. PARTITUS. Plate xvi., fig. 7. 
Agnostus partitus. ‘lrans. Roy. Soc. Can., vol. ili., pt. iv., p. 
68, pl. viii., fig. 2a (mot 2b). 
Cephalic shield elongate semi-elliptical. Dorsal furrow dis- 
tinctly impressed; marginal fold sharp and narrow. Glabella 
cylindro-conical, obtusely pointed in front, expanded at the 
base; anterior lobe obtusely pointed, less than a third of the 
glabella’s whole length ; posterior lobe strongly elevated and 
obtusely pointed behind; basal lobes triangular, depressed to 
the level of the cheeks. Cheeks somewhat narrower in front 
than at the sides ; divided in front by a distinct furrow that con- 
nects the dorsal and marginal furrows. 
The heads of this variety are hardly distinguishable in form 
from the next, but they are all small, and it is found with an 
older subfauna; it is therefore kept separate. The pygidium is 
unknown. 
Size.—Length and width of the head shield 24 mm. 
Horizon and Locality.—The grey shales of Div. 1 c¢, 1, at 
Porter’s Brook and Hanford Brook, St. Martins, N. B., Canada. 
Infrequent. 
Var. AcuTILoBus. Plate xvi., fig. 8. 
Agnostus acutilobus, Trans. Roy. Soc. Can., vol. iii., pt. iv., p. 
i2a plevil., fies LO. 
Body elliptical elongate. Cephalic shield semi-elliptical, 
somewhat longer than wide. Dorsal furrow lightly impressed. 
Marginal furrow and fold sharply defined. Glabella subconical, 
widest behind, obtusely pointed in front; at the widest part of 
the posterior lobe it is one-third of the width of the head shield, 
and its length is about three-fourths of that of the head shield ; 
the glabella is divided into four lobes, of which the anterior is 
one-third of its length and is subtriangular; the posterior lobe 
extends to the base of the shield. It bears an elongated ridge 
on the anterior half, where it is higher than it is behind ; two 
faintly marked lateral furrows are just discernible on the lateral 
edges of this lobe. The two basal lobes of the glabella are com- 
paratively large; they are divided from the rest of the glabella 
by a sigmoid furrow, and are depressed below the level of the 
