204 | TRANSACTIONS OF THE [may 18, 
Amended Description.—Form conical with an oval base and 
bluntly pointed apex. Viewed laterally the cone has a dorsal 
edge moderately convex, and a ventral edge slightly concave ; 
the base is straight for two-thirds of its length and turned up at 
each end. The orifice of the cone is a flattened oval twice or 
three times as long as wide; the side of the cone is encircled 
by about six undulations of growth which arch upward around 
each end, corresponding to the curving basal margin. The cone 
has in its apex a short, annulated tube, about as long as the space 
between two of the transverse ridges of the surface. The upper 
two-fifths of the cone is thickened, and between this part and 
the base the cone has four perforations along the dorsal slope, 
and there are perforations (four?) also along the ventral slope. 
On the inner surface of the cone there are sharp, engirdling 
grooves corresponding to the rounded ridges on the outside, and 
opposite the dorsal and ventral perforations these grooves, where 
they meet from the opposite sides of the cone on its inside, are 
enlarged into a cup-shaped cavity. 
Sculpture.—The rounded ridges of the surface are each tra- 
versed lengthwise by about six striz, visible only with a lens. 
Size.—Height 44 mm; length of base 5 mm. 
Horizon and Locality.—Fine grey shales of Div. 1 ¢?, at St. 
John and Hanford Brook, St. Martin’s. Infrequent. 
This fossil has a thicker and firmer test than the two preced- 
ing kinds. The perforations recall those seen on the appendages 
of crustaceans as for instance those of Phyllopods, figured by 
Barrande,* and it appears probable that they are the points of 
attachment of mobile spines. Clarke figures a row of such in 
Strobilepis, but not as being connected with the terminal plate. 
STENOTHECA NASUTA. (Plate XIV., figs. 6a and 6b.) 
Stenotheca nasuta, Trans. Roy. Soc. Can., vol. iii., pt. iv., p. 
58, pl. vi., fig. 13. 
Amended description.—Conical, subtriangular in side view, 
with deeply concave ventral slope and convex dorsal slope. 
Orifice of the cone strongly arched. As preserved in the shale 
there isa smooth raised band both on the dorsal and ventral 
slope, that on the former being wider; in the space between are 
about six rounded concentric ridges, parallel to the base. 
Sculpture.—The surface is smooth, or nearly so, except on 
the dorsal band, where a number of faint striz, concentric to 
the apex, are made visible by a lens. 
Size.—Height, about 24 mm.; length of base, 35 mm. 
*Systeme Silurien de Boheme, vol. i., supp., pl. 19, figs. 6, 8, 10, &e. 
