172 
XArTILOIDEA. 
This species is only known by casts, therefore the test has not 
been seen. The impression of the shell-muscles is distinctly seen 
upon the specimen figured (IS’o. C. 2549). 
Remarhs. Compared with S. dorsalis, Phill., sp. (Geol. of York- 
shire, pt. ii. 1836, p. 231, pi. xviii. if. 1. 2), the present species is 
found to differ in its much more broadly rounded periphery and 
wider aperture ; the septate portion of the shell is also much larger 
Tig. 29. Fig. 30. 
Fig. 29. Solenocheihis latiseptatus . — Peripheral vie-^v of cast, showing the posi- 
tion of the siphuncle. The thin curved line at the top is the impression 
of the shell-muscles upon the cast of the body-chamber. 
Fig. 30. Solenocheihis Caledonicus. — a, peripheral view, showing three of 
the septa ; h, detached septum, showing siphuncle, not quite in the 
median line. 
These figures (29 and 30) represent specimens in the British Museum, 
in proportion to the hody-chamher than in Phillips’s species, and 
the septa very considerably wider apart. 
Horizon. Upper Limestone Group (Carboniferous Limestone) ; 
Calciferous Sandstone. 
Locality. Arden Quarry, Yitshill, near Glasgow ; Closeburn, 
Dumfriesshire. 
Represented in the Collection by two examples. 
