GASTEROPODA. 111 
Ammonites Braikenriper, Sow, Plate XIV, fig. 1. 
AMMONITES TRIPTOLEMUS, Bean. MS. 
? —_— BralKENRIDGII, Sow. 1813. Min. Con., t. 184. 
— _ D’Orb. Ter. Jurrass., t. 135, figs. 2, 3. 
A. Testa discoided, anfractibus ('—6) expositis, subrotundatis, costatis ; costis (30—36) 
eaterné tuberculatis, in medio laterum bifidis, subinde trifidis, continuis ; dorso subconvexo ; 
apertura transversd, subdepressd, eaterné angulatd. 
A discoidal shell, with 5—6 exposed, somewhat rounded and costated volutions ; with 
30—36 marginal coste, tuberculated externally, from each of which arise, about the 
middle of the side, 2 and sometimes 3, rather obtuse smaller ribs, passing over the back ; 
aperture wider than high, somewhat convex, with angular sides. 
This Ammonite (forwarded to us with the name, 4. Zriptolemus), belonging to the 
section Coronarii, appears to be intermediate to 4. Humphriesianus and A. Braikenridgii, 
with the latter of which it is the more closely allied, but differmg from it by the smaller 
coste (in the cast) not being wholly enveloped by the later volutions. We regard the 
specimen figured as only the adult state of this species. 
Locality. Near Scarborough. 
CLass—GASTEROPODA. 
Auaria Puruurpsit, D’Ord. sp. Plate III, fig. 5; and Plate XV, figs. 15, 15a. 
? RosTELLARIA HAMUS, var. 3, Deslongchamps. 1842. Mem. Soc. Linn. de Normandie, 
tom. vii, p. 174, t. 9, fig. 36. 
(See description, avfea page 18.) 
We have provisionally retained (page 18) M. D’Orbigny’s specific name for the 
Yorkshire shell, believing that the one figured as Rostellaria composita, by Phillips, pre- 
sented certain differences from that described in the ‘Min. Conch.,’ occurring in the 
Oxford Clay of Weymouth. But Mr. Sowerby distinctly states that he has received the 
same species from near Scarborough, so that the differences may prove, when a larger 
number of specimens shall have been examined, to be due merely to variations arising 
from local conditions. The Yorkshire shell appears to be identical with Rostellaria hamus, 
var. 8, of M. Deslongchamps, cited above, from the Great Oolite of Ranville. 
Locality. Near Scarborough. ‘This species is also found in the Inferior Oolite of 
Yorkshire, and in the same formation at Dundry and Bridport. 
