Leptoplastus in the Acadian Cambrian Rocks. 487 
Hypostome (found loose with this species), sub-rectan- 
gular, rounded in front, truncated at the posterior corners ; 
arched upward across the middle, depressed at the end and 
having there a narrow upturned fold. 
Sculpture. Crust smooth. 
Size. Length of middle piece of head 6 mm., width 10 
mm. Length of movable cheek 11 mm., width 4 mm. 
Lengthof pygid. 4 mm., width 7mm, Length of hypos- 
tome (?) 3 mm., width 2 mm. 
Horizon and Locality. Calcareous layers in fine dark olive 
grey shales. Div. 3, Band a. St. John Group on Long 
Island, Kennebecasis River, N.B., in company with Agnostus 
pisiformis, &e. 
This species is very near to L. stenotus, but differs from it 
(as figured by Angelin) in its conical glabella, more flaring 
cheek and spine and wider border to the pygidium. 
Lepropuastus Spinicer. N. Sp. 
Head. Only the centre piece known. This is trapezoidal in 
outline, with a spinous projection in front and another behind. 
It is strongly vaulted transversely and has a distinct anterior 
marginal fold produced at the axial line into a sharp spine. 
The spine projects forward, and is about three-quarters of 
the length of the glabella. Glabella ovate-conical, with two 
pairs of short, slightly oblique furrows. Occipital furrow 
distinct, crossing the axis; occipital ring, broad in the 
middle, bearing a spine directed backward. Fixed cheeks 
strongly arched. lHyelobes prominent. Posterior furrow 
and fold distinct. 
Sculpture. Crust smooth, 
Size. Length, excluding spines, 24 mm., with spines, 4 
mm.: width, 4 mm. 
Horizon and Locality. Occurring with the last species. 
Among the Swedish Leptoplasti, Z. raphidophorus is the 
one which in size compares to this, but it differs in many 
details. It also is a spinous species, but is not shown to 
possess ae peculiar spine at the apex of the shield, which 
