8 
NATJTILOIDEA. 
form a sinus on the inner side. The ornaments consist of, first, 
sharp non-separate ribs, at first | the diameter apart, becoming 
closer to an average of ^ the diameter, though appearing still closer 
by compression, and finally dying off on the body-chamber on 
approaching the aperture — these rather undulate, or are oblique, 
sloping backwards to the exterior ; secondly, there are fine riblets 
parallel to these, numbering from 10 to 20 in the interval between 
two ribs, and degenerating into lines of growth on the uu ribbed 
part. The septa lie parallel to the ribs in the intervals between 
them, and are thus about ^ the diameter apart ; their convexity is 
between and i the diameter. The siphuncle is small and central. 
The type is the longest species. The greatest diameter of the more 
curved part is -f inch.” 
Remarks. The specimen representing this species in the Collection 
consists only of a very small fragment, half buried in the matrix, 
but exhibiting the sculpture characterizing Sowerby’s species. It is 
very doubtful if this is a Lituites at all, though the curvature of the 
apical portion in the type specimen figured by Sowerby suggests that 
the shell may have been at first coiled. The presence of Lituites in 
the British rocks must, for the present, be considered as very far 
from satisfactorily determined. 
Horizon. Lower Ludlow. 
Locality. Leintwardine, Herefordshire. 
Bepresented in the Collection by a very small fragment presented 
by J. E. Lee, Esq., E.S.A., E.G.S. 
Genus OPHIDIOCERAS ^ Barrande. 
( Ophioceras, Barrande, 1865 ^.) 
Gen. Ghar. Shell consisting at first of numerous symmetrically 
coiled, contiguous whorls, with little or no central vacuity. The 
section is more or less rounded, but there is a fiat band running 
along the peripheral margin which evidently results from the filling 
up of the ventral notch in the aperture. A portion of the last 
whorl finally frees itself from the coiled part and is produced into 
a short straight piece about of a whorl in length. The aperture 
is slightly expanded and trilobate, one of the lobes being longer than 
the other two (fig. 2, cl). The sutures are simple. The siphuncle 
appears to vary in position according to the age of the individual ; 
in the young it is nearly central, while in the adult it is very near 
^ Syst. Sil. de la Boheme, 1867, vol. ii. pt. i. p. 174. 
2 Ibid. 1865, vol. ii. pt. i. pis. xlv. & xcvii. 
