CERITHIUM. 149 
Goldfuss, and Cerithium (Cryptaulax) tortile, Héb. and Desl., which was clearly a 
mistake, as these two are totally different species. He was not so far wrong in 
including Melania wndulata, Deslong., as this is certainly in part a representative 
species. The same author also regarded Chemnitzia? vetusta, Morris and Lycett, 
as a species distinct from that of Phillips, and already included under C. flexwosum, 
Minster. 
Description.—Size variable; 15 mm. is the length of a fair-sized specimen. 
The spiral angle is about 18°. Shell elongate to elongate-ovate. Spiral angle 
regular; whorls ten to twelve, flat to subconvex, anterior whorls turrited, suture 
close. The posterior whorls are very flat, with longitudinal costz, which are 
straight and extend from suture to suture, almost without spiral decussation. 
By degrees the whorls become more convex, the coste becoming arcuate, and in 
very well-preserved specimens decussated by fine spiral lines, which cause the 
cost to be granular. 
In full-sized specimens the body-whorl is slightly ventricose, and, if well pre- 
served, the spiral decussations are shown; in this case the uppermost row of 
spirals assumes a slightly muricated character. Base full and spirally striated, 
with sometimes a slight prolongation of the axial coste. Aperture broadly ovate, 
with a sharp angle at the posterior extremity ; inner lip somewhat expanded on 
the columella ; anterior canal fairly developed (in all available specimens the end 
of the canal has been broken off). 
Varieties.—The original figure of Terebra vetusta, Phil., represents a specimen, 
either from the Millepore or Grey Limestone, which is in that condition where all 
the fine spiral lines are obliterated. This is perhaps the most usual condition for 
specimens. It is partly on account of this appearance that Terebra vetusta has 
been so often referred to “ Chemnitzia.” 
Chemnitaia ? vetusta, Phil., of Morris and Lycett, represents a more perfect 
specimen from one or other of the same beds. The spiral ornaments are faintly 
distinguishable, more especially in the anterior whorls, and the longitudinals are 
somewhat more arcuate. Hence Braun’s reference to Cerith. fleruosum. In the 
Dogger this stage of C. vetustwm is not uncommon. 
So much as regards Yorkshire varieties. Elsewhere in the Inferior Oolite of 
England there are specimens, some with granular, some with continuous cost, 
straight or flexed, which may be referred to C. vetustum. I have several such 
from the Parkinsoni-zone of the Cotteswolds. When in bad condition C. vetustum 
is the most suitable name. 
Relations and Distribution—Under the head of relations little more need be 
said. As regards distribution, 0. vetustum occurs in the Dogger, where it probably 
represents an incomplete stage of the next species. The best specimens, as 
regards condition, are obtained from the Lower Division of the Scarborough 
