35 
\ 
SOLARIUM. 
Gen. Char. Shell univalve, depressed,, conical, 
nearly discoidalf umbilicated ; Umbilicus 
spreading, crenulated or denticulated at the 
margin of the volutions : Aperture approach- 
ing to quadrangular. Axis oblique. 
SOLARIUM patulum. 
TAB. XL— The lower right hand figures* 
Spec. Char. Depressed; whorles smoothish, mar- 
gins keeled and crenulated ; Umbilicus spread- 
ing ; margin of the umbilicus strongly den- 
ticulated. 
Lamarck Ann. du Mns. 4. 53. and 8. Tab. 35. f. 3 . 
Diameter from three-eighths to three-fourths of an inch. 
Length nearly half its width. The umbilicus is curiously 
and beautifully ornamented with a crenulated border, sur- 
rounded by a row or two of small denticulse. The flattish 
disk-like surface swelling a little, has longitudinal striae 
with more or less fine transverse marks over it. The outer 
angle of the shell is sharpest, the upper surface of the edge 
is milled, as it were, witli oblique transverse striae causing 
small oblong risings like the oblique milled edges of Gui- 
neas. The shell is also longitudinally striated beneath. 
Found rather abundantly in the dark clay stratum at 
Highgate. It approaches very much to Brander’s tab. 1. 
fig. 7 and 8. but is nevertheless distinct ; it may be considered 
cotemporary with the Hampshire fossils. 
TAB. XI *—Left hand lower figure . 
This specimen is from Highgate. It appears to be an old 
specimen of the last species, in which the crenulations of 
the umbilicus, and the milling of the upper edge, are be- 
come nearly obsolete. The shell itself is in a very decayed 
state, but in those parts of the umbilicus w here any of the 
shell remains, the crenulations have the appearance of rag- 
ged transverse wrinkles, except at the inner part of the um- 
bilicus, where they resemble those of the last. 
TAB. XI. — Left hand upper figure. 
This is also from Highgate, it appears to be the cast of the 
inside of Solarium patulum, but is larger than usual, and 
there is some doubt if it be not the inner cast of a new spe- 
cies. It is however remarkable, and worthy of a figure., 
