242 G. F. MATTHEW ON THE 
the anterior marginal fold are about thirteen (13) lines (those toward the inner side more 
closely set), and of these about six (6) go around the genal angle outside of the flat area: 
half-way down the spine are about fifteen (15) lines evenly distributed. No raised lines 
were observed on the posterior marginal fold. 
Length, about two inches. 
Found at Portland in Division 1c. 
No. 8. (Fig. 2). 
Distinguished from the two preceding and from No. 5 by its small genal spine. 
The flat area is more triangular than No. 1, but less so than No. 2; as in the former, 
the inner end of the cheek is wide, being nearly half of the length of the posterior margin. 
The anterior marginal fold and spine are strongly arched. The spine is about one quarter 
longer than the posterior margin, and much narrower than the anterior marginal fold. 
Sculpture—Vhe anterior marginal fold has on the upper side, at the genal angle, about 
eighteen or twenty (18-20) fine raised lines more evenly distributed than those of the pre- 
ceding forms. The flat area appears smooth and shining, but under the lens is seen to be 
minutely granulated. 
Length, about one and a half inches. 
Found at Radcliff’s Mill-stream, Simonds: from Division 1d, and therefore higher in 
geological position than any of the others. It may be the young of a variety of No. 5. 
In the wide posterior end of the flat area, and in the numerous fine raised lines of the 
anterior marginal fold, it exhibits analogies to P. quacoensis. 
No. 4. (Figs. 7 & 12. (9 & 10?) 
Distinguished by the long eyelobe, and the narrow, anterior end of the flat area. 
The inner end of the cheek is about one-third of the length of the posterior margin 
(longer in adults). The spine is not quite as long as the anterior marginal fold, and the two 
parts are regularly curved. The anterior third of the flat area is about half as wide as the. 
corresponding part of the marginal fold. 
Sculpture —On the upper side of the anterior marginal fold are about eight (8) lines, 
and about ten are found half-way down the spine. The “surface of the flat area is 
minutely but distinctly granulated, but these granulations are usually not distinguishable 
without a lens: in adults this part of the cheek is somewhat undulated. There are large 
specimens apparently belonging to this species in which the raised lines of the anterior 
marginal fold are reduced to five (5), and the surface of the flat area is smoother than in 
medium and smaller sized cheeks. 
Length, about two inches. 
Found at Portland and Radcliff’s Stream in Division 1e. 
This cheek may belong to P. eteminicus. 
No. 5. (Fig. 8). 
Distinguished from all the others by the numerous raised lines on the anterior mar- 
ginal fold and genal spine, and by the breadth and flatness of these parts. 

