Mr. J. Lycett on the Upper Lias of Gloucestershire. 159 
Cephalopoda. | Gasteropoda. 
Pleurotomaria. 
Ammonites bifrons, Brug. Turbo capitaneus, Miinst. 
falcifer, Sow. 
— communis, Sow. Conchifera. 
—— heterophyllus, Sow. Astarte lurida, Sow. 
cornucopie, Y. & B. Lucina ? 
— Jurensis, D’Orb. Tancredia leeviuscula, n. sp. 
—— Lythensis, Y. & B. Posidonia Bronnii, Miinst. 
crassus, Phil. Placunopsis sparsicostatus, n. sp. 
annulatus, Sow. Nucula Hausmanni, Rem. 
—— Iminstrensis, n. sp. Pecten. 
Belemnites compressus, Voltz. _ Gresslya gregaria, Rem. sp. (G. An- 
tripartitus. glica, Ag.) 
Nautilus latidorsatus, D’ Orb. Lima gigantea, Sow. 
—— sinuatus, Sow. —— bellula, Mor. & Lyc. 
Notes on the Testacea. 
Ammonites bifrons. A variety with compressed sides, in which 
the falciform ribs are but little prominent. A few examples 
occurred of the ultimate condition of growth, in which state it 
may readily be mistaken for a distinct species, and probably 
constitutes the A. Hildensis of Simpson. The coste have dis- 
appeared upon the whole of the last volution, which presents 
only densely arranged fine falciform lines which pass over the 
back and the keel; the lateral sulcation has become indistinct 
through the flattening of the sides of the volution ; the back has 
lost its rectangular figure and become rounded, sloping obliquely 
upon each side from the keel, and the two dorsal grooves have 
disappeared ; the keel itself has become more elevated and con- 
spicuous. The inner or smooth portion of each volution over- 
wraps and conceals the costated portion of the preceding volu- 
tion, so that the entire aspect of the shell is smooth, and it is 
only by breaking away a portion of the last volution near to the 
suture that the ribs of the next volution can be exposed and 
the identity of the species proved. It occurred abundantly. 
A. communis. Specimens were indifferently preserved, but 
exhibited some of those varieties in the arrangement of the dor- 
sal ribs, and in the general figure, which perplex collectors who 
desire to separate them into the forms named 4. communis, 
A. Hollandrei, and A. Braunianus,—a perplexity which is in no 
degree lessened by the study of numerous specimens. Further 
investigations into these forms are desirable. 
A. heterophyllus. Badly preserved examples, and few. 
A. cornucopia (A. fimbriatus, Sow.). A single fine example 
in one of the higher beds. Some casts of young forms, appa- 
rently of this species, have been procured in the lower zone of 
the Cynocephala-stage at Nailsworth, , 
