11 
Streptelasma fragile n. sp. 
Plate I, figures 1, 2 
Corallum small and slender, the apex as a rule slightly curved. All 
specimens are partly broken, the fragile cup usually being destroyed. 
One large, fairly well preserved specimen measures 15 mm. in length, 
6 mm. in diameter. Epitheca somewhat wrinkled, faint longitudinal 
striae present. Calyx circular, but sections at the base of the cup are 
slightly compressed, the narrower diameter being from the concave to the 
convex sides of the slight curvature in the corallum. Calyx three-fourths 
length of whole corallum, a long, gradually tapering fragile funnel, trun- 
cated, not pointed, at the bottom. Pseudo-columella not protruding. 
Secondary septa minute but distinct. Primary septa 15 to 20. Cardinal 
septum on the short diameter. Tetrameral arrangement of the septa 
well developed. 
Figure 2. Streptelasma fragile, diagrammatic relation of septa, x'3. 
S. fragile . is readily distinguished from other described Ordovician 
forms by its size and slender proportions. The broken tips of the species 
resemble specimens of the Silurian S. pygmaeum, but a fairly complete 
specimen is easily recognized by the larger size, more slender form, and 
the proportionately deeper calyx of S. fragile with its truncated rather 
than pointed base. S. fragile differs from S. conulus Rominger in its greater 
size, in having faint longitudinal strise, in the slight curving at the apex, and 
in the arrangement of the principal septum. 
Horizon and Locality. Richmond: Beaverfoot. From the Stoddart 
Creek section, Windermere district, Rocky mountains, British Columbia. 
A somewhat broken, small Streptelasma probably belonging to this species 
is among the specimens from three-fourths mile east of the trail on the 
east slope of Palliser pass. 
Streptelasma prolongatum n. sp. 
Plate I, figures 3, 4, 5; Plate XI, figure 2 
Corallum simple, slightly curved, rapidly widening. In some cases 
attaining large proportions, several specimens approaching 40 mm. in 
the longest diameter. Outer surface of the epitheca thin, comparatively 
smooth in the younger stages of development, becoming more wrinkled 
with age. Longitudinal strise on the outside corresponding to the 
secondary and primary strise within. The strikingly elongated pseudo- 
fossula is the cause of a sharp angle upon the slightly curved side of the 
