86 AMMONITID&. 
incomplete Ancylocere. /. cristatus, d’Orb. (xxxii,29). Gault; 
Southern France. 
Turritires, Lam., 1801. 
Htym.— Turris, a tower, lithos, a stone. 
Distr.—37 sp. Gault to Chalk; Europe. 7’. costatus, d’Orb. 
(xxxili, 37). J. Boblayi, d’Orb. (xxxiii, 38). 
Shell spiral, depressed to elongate, sinistral; sutures six-lobed, 
foliated ; aperture often irregular. 
The animal of Turrilites was perhaps dibranchiate by the 
atrophy of the respiratory organs of one side. 
HETEROCERAS, d’Orb., 1847. Shell like Turrilites, but last 
chamber somewhat produced and recurved. 5 sp. Cretaceous ; 
Europe, United States. TT. Hmericii, d’Orb. (xxxiii, 39). 
HELICANCYLOCERAS, Gabb, 1869. Spire less elevated, volutions 
less decidedly in contact. 
HELICOCERAS, d’Orb., 1842. (Helix [helicos|, a spiral, ceras, 
a horn.) Shell spiral, sinistral; whorls separate; annular coste 
passing uninterruptedly over the siphonal side. 11 sp. Inferior 
Oolitic (?) to Cretaceous ; Europe, India, United States. 
PATOCERAS, Meek, 1876. Coste interrupted on the siphonal 
side, leaving a narrow, smooth space along the whole length of 
the same. TZ. Teilleuxii, d’Orb. (xxxiii, 36). Jurassic. 
Bacurites, Lam., 1801. 
HKtym.—Baculus, a staff. Syn.—Cyclomera, Conrad, 1866. 
Distr.—20 sp. Cretaceous; Europe, Chili, India, United 
States. B. anceps, Lam. (xxxii, 30). France. B. baculoides, 
d’Orb, (xxii, 31). 
Shell straight, elongated, conical; suture foliately lobed ; last 
chamber large; margin of aperture dorsally produced. 
The baculite limestone of Normandy is so called from the 
numerous remains of the shells of this animal which it contains. 
Conrad has given the name Cycloceras to a Baculite figured 
by him, but without generic characters ; afterwards, finding that 
name preoccupied by M’Coy, he changed it to Cyclomera, still 
giving no diagnosis. 
Meek divides Baculites into two subgeneric forms, which, he 
remarks, are possibly distinct genera. 
BACULITES, Lam. (typical). a. Shell straight throughout ; 
aperture directed forward ; lip with lateral sinuses directed back- 
ward ; the projection of its siphonal margin, straight, and its anti- 
siphonal margin convex in outline; interior without regularly 
disposed ridges. 2B. vertebralis, Lam. 
(?) b. Shell straight posteriorly, but with the non-septate part 
gently arcuate; aperture a little oblique; appendage of siphonal 
side of lip arching slightly with the general curvature of the non- 
