278 G. F. MATTHEW ON THE 
:HYPOSTOMES. 
No. 1 (Fig. 22). 
About as wide as long. The front lobe or dome iselongate-semicircular. A lobe pro- 
jects on each side beyond the neck of the hypostome about one-fifth of the whole tranverse 
diameter. 
The neck of the hypostome is continuously elevated on the axial line, not furrowe 
across as in the succeeding forms. A furrow extends inward from the back of the late- 
ral lobe of the dome on each side to an impressed point on the side ofthe neck. The sides 
of the neck are depressed as far as the posterior marginal fold, where the depressed part is 
widest. 
The ears or raised margins at the sides of the neck are broken off, but appear to have— 
been thin; they extend backward beyond the posterior margin in a short spine, which is 
about one-third of the length of the ear. 
The posterior marginal fold is moderately elevated, runs backward for about one quar- 
ter of its length, and then suddenly turns forward and upward toward the axial line. 
Sculpture—The cast of the inner surface of this hypostome, except at the neck and 
along the axial line, is covered with roughly parallel, anastomosing, raised lines, which 
_bend around the front of the hypostome ; along the axis for three-quarters of its length 
they are nearly parallel. 
Length, exclusive of spine, 1} inch. Width, nearly one inch. 
Locality,—Portland, N.B., in Div. 1c. This hypostome was found with fragments of 
the cephalic shield of a large, undescribed paradoxides. 
No. 2 (Figs. 23 § 24). é 
General form much as the last, but differs in the following particulars :—The neck is 
crossed by a light furrow; the ear is thinner than in No. 1,and is prolonged in astrong 
spine abruptly and obtusely pointed ; the posterior marginal fold is thinner and less promi- 
nent, and the margin is gradually rounded backward, and not angulated as in the pre- 
ceding form. Spine about half of the length of the ear. 
Sculpture —Anastomosing raised lines as in the last, bend around the front and poste: 
rior part of the central portion of the hypostome; the lateral lobes are also covered with 
dichotomous lines, that branch off from those that go around the front margin of the 
hypostome; The ear and the adjoining depressed area are traversed by about six lines, 
most of which run out on the spine, where they run parallel to two lines, which come 
out upon the spine from the posterior marginal fold; the fold is traversed by three or four 
lines, and the neck of the hypostome by a number of faint lines, more widely spread: 
Length, exclusive of spine, and width, each about one inch. 
Locality.—Portland, N. B., in Div. 1c. From the dark, fine-grained layers in which 
P. pontificalis is found. 
No. 3 (Figs. 25, 26 § 27). 
Dome semicireular and about one-third wider than the neck of the hypostome. A 
well marked furrow separates the two parts. This furrow is most strongly impressed in 
the outer third, where its course is diagonal to the axis of the hypostome. 

