278 
INFERIOR OOLITE AMMONITES. 
by a very small carina, on each side of which is a slight depression.^ No inner 
margin. Inclusion very little. Umbilicus large and open, ornamented with 
numerous ribs. 
This very characteristic species was first figured by Dumortier, who appended 
to it an MS. name given by Thiolliere. Dumortier noticed as a character of this 
species " Three or four annular depressions irregularly placed upon each whorl." 
My specimen, which however is not well preserved, shows two well-marked 
depressions upon the outer whorl ; and occasionally poorly-marked depressions 
may be seen in the inner whorls in places. 
As a synonym of this species I have quoted Harpoceras ehnagum, de Gregorio. 
This author says that his species differs from Am. Dumortieri "by a more 
developed last whorl, and the ribs more rounded and less prominent ; but still it is 
as well to consider it a mutation." It may be remarked that these points of 
difference in the ribbing might result a good deal, as my specimen shows me, 
from whether the test was absent or present, and also from the state of 
fossilization. 
This species is decidedly rare. I am indebted to the kindness of Mr. J. E. 
Clark, F.G.S., for the figured specimen, which is the finest example that I know 
from this country. During an excursion that we took together under the Burton- 
Bradstock Cliffs he pointed it out to me in a block of fallen sandstone. I have 
another specimen, a fragment without label, from my father's collection ; it seems 
to have come from the bottom of the Yeovil Sands, Bradford Abbas, Dorset. I 
have another small specimen kindly sent to me by Mr. E. Wilson, F.G.S., "from 
a field-drain at the east end of Dundry," out of a slightly argillaceous matrix. 
In figs. 6 and 7 of PI. XXXIX are shown the side and front views of the 
specimen from Burton Bradstock. The top constriction in fig. 6 is a little 
exaggerated ; while the carina and adjacent area at the top of fig. 7 should be a 
trifle more depressed. Fig. 8 gives a view from above, in which the carina and 
the ribs beyond the constriction are just a little too much pronounced. Fig. 9 
is the suture-line. 
Catulloceeas iNSiGNisiMiLE {Bvauus). Plate XXXIX, figs. 12 — 14. 
1867, Ammonites insignisimilis, Brauns. Stratr. u. Pal. Hilsmiilde ; Palson- 
togr., siii, pi. xxv (v), figs. 5, 6, 7. 
The fragment figured is all the material I can obtain. It diff'ers from both 
1 This depression is really due to the abrupt eudiug of the ribs short of the carina. It is not 
nearly so conspicuous where the test is present. 
