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Transactions. 53 
considerable length. The breadth of the adult portion of the 
stipe from the solid axis to the cell mouth is from one to two 
lines. The axis is capillary, the common canal is broad, some- 
times attaining a width of ,\,th of an inch. The cellules are 
_long, slender, and pointed, their superior margins slightly convex, 
and having a general direction at right angles to the axis ; their 
inferior margin more extensively curved, the inner or lasal por 
tion being sharply inclined to the axis, while the outer half is 
nearly horizontal. Each cellule is of a triangular shape, the base 
resting on the common canal, the cell apertures being at the 
apex. The cellules are separate, from 20 to 24 in the inch, their 
general inclination being slightly upwards, nearly at right angles 
to the axis. Locality—Dobb’s Linn, Garpel Glen, é&e. 
Monograptus Sedgwicku, var. triangulatus.—This is a well 
marked variety of M. Sedgwickii, and not a distinct species. The 
stipe is simple and moniprionidian, and is more or less curved; 
beginning with a small radical and a slender curved proximal 
portion, which gradually straightens as it reaches full develop- 
ment. The axis is capillary ; the common canal is slender, and 
very much narrower than in the normal form. The cellules are 
from 20 to 30 in an inch, nearly at right angles to the axis, and 
sometimes approaching the appearance of a Rastrite so nearly as. 
to be mistaken for such. Locality—Dobb’s Linn and Beld Craig. 
Monograptus lobiferus (M‘Coy).—In this species the stipe is 
linear, monoprionidian, often of great length. ‘The full grown 
individual reaches a breadth of one-tenth to one-twelfth of an 
inch, The axisis slender. The common canal is rather broad and 
well marked. Cellules are nearly at right angles with the axis, 
but having a slight upward inclination. Their upper margin is 
curved, terminating in obtusely rounded lobes, in which a notch 
on the under side separates the rounded extremity from the 
oblique descending margin (M‘Coy). The cellules in full grown 
specimens vary from 16 to 18 in the space of an inch. The base 
is slender and curved, the common canal having a comparatively 
greater width. The cell, as is occasionally well shewn, opens at 
the notch in the under side of the cellule. Locality—Dobb’s 
Linn, Beld Craig, &c. 
Climacograptus teretiusculus.—This genus was at first described 
by Professor M‘Coy, and named by him Diplograptus rectangularis. 
Itis very abundant, having a wide range passing up through the 
Skiddaw States, Lower and Upper Llandeilo, Caradoc, and Lower 
