384 On Lingulasma^ Etc. — Ulrich. 
ly and longitudinally, greatly elevated in front and prolonged 
anteriorly into a remarkably developed median plate. Just in 
front of the small transverse ridge already described, there is 
a deep excavation and at its bottom a triangular, arched, del- 
tidium-like space (h). From the abruptly terminating an- 
terior side of this triangle, which is supposed to represent the 
suh-cardinal scars, a small and gradually diminishing ridge 
extends anteriorly. This divides, at its posterior end, a well 
marked subpentagonal scar (;j)) supposed to be the post 
median^ and, further on, the scarcely impressed median scars 
(m). The position of the anterior scars is faintly indicated at 
the point of junction between the median septum and anterior 
end of the platform; likewise the scars of the transverse pair 
at the antero-lateral angles of the platform. The umbo-lateral 
scars are well defined and situated on the posteriorly converg- 
ing sloping sides of the cavity at whose bottom is placed the 
post-median scar. The sub-cardinal, umbo-lateral, and post- 
median scars together cover a somewhat transversely elonga- 
ted space rudely rhomboidal in outline. Of all the scars the 
lateral pair is the strongest. These are of oval form, oblique, 
and placed one on each side of the medians. 
Type : Lingulasma scMicherti., n. sp. 
There are two English species, Lingida granulata Phillips, 
and L. temdgranulata McCoy, and one Canadian form, Z. 
Ganadensis Billings, which I expect confidently will prove to 
possess the internal characters of Lingulasma. These three 
species agree with Z. schucherti not only in the general form 
of their shells, but also in possessing so-called " granulations " 
on the concentric strife, which, being arranged in radial series, 
impart a reticulate ornamentation to the surface. These 
granulations, I suspect very strongly, are not simply solid 
elevations of the surface but, rather, of the nature of short 
tubes, or, possibly, the broken bases of tubular spines similar 
to those of Siphonotreta. Should my suspicions concerning 
the interior of these species and the tubular character of the 
" granulations " prove well founded, then an additional dis- 
tinguishing peculiarity may be added to the diagnosis of 
Lingulasma. 
In entering upon a discussion of the relations of this re- 
markable genus, I may at once express my conviction that we 
have before us a widely diverging but transient type or spur 
