PSEUDOMELANIIDyE. 
235 
separated by a wide sutural sulcus, are angular and strongly bicarinate, the upper 
Carina being the most prominent. Besides the two central carinee a fine spiral 
line is noticeable towards the top and bottom of each whorl, and in the last 
whorl the lower of these has considerable prominence, forming the edge of the 
base. The cross-hatchings in this specimen are wide apart and considerably 
oblique to the axis. 
The Beaminster specimen most resembles pi. viii, fig. 10, of the “ Fossils of 
Montreuil-Bellay,” but there are elements of difference. It has also some affinity 
with “ Gerithium” amoenum, Desl. (‘Mem. Soc. Linn. Norm.,’ vol. vii, p. 201, 
pi. xi, figs. 16, 17, 18). It is most probably one of the Mathilda-\\ke Turritellxd 
Family— 
Shell elongate, turrited, many-tvhorled, resembling that of the Melaniidx ; 
aperture oval, usually entire, seldom notched or channeled at the base; columella 
simple or folded anteriorly, lip thin, arcuate, slightly sinuousF — Fisohek.^ 
I have already indicated (pp. 8 and 144) the reasons for no longer making use 
of the old term “ Ghemnitzia” for any of the MelaniaAdke shells of the Jurassic 
rocks. As regards the genus, Pseudomelania (including Gemmellaro’s sections — 
Fseudomelania as restricted, and Bhabdoconcha), there is no difficulty. In this we 
perceive a very natural group of which the Corallian species, Pseudomelania 
Heddingtonensis, may be taken as the type. The genus is also well represented in 
the Inferior Oolite. 
Neither is there much difficulty with respect to such a shell as Bourguetia 
{Phasianella) striata. This we can readily refer with Fischer to the Pseudo- 
melaniidae. Then comes the question what are we to do with the numerous, 
1 Attention should here be drawn to some curious fossils lately discovered by Mr. Crick in the 
Upper Lias of Heyford (see PL xvii, fig. x). These resevahle Mathilda euglypha, Laube. I would 
scarcely aver that the two forms are specifically identical. M. euglypha has a much larger habit, 
being at least 10 mm. in height, whilst the Heyford specimens do not average more than 3 mm. 
Moreover, if we can trust to the enlargement in Laube’s figure, there is much more decussation of 
ornament in M. euglypha. The spiral angle is about the same, viz. 24°. Our fossil exhibits the 
embryonic button in an excellent state of preservation. 
The specimens on which the drawings and description of this species of Mathilda are based have 
been kindly lent to me by Mr. Crick. I suggest that the species be known as Mathilda Ckickii. 
^ “ It would be curious to investigate from the point of view of descent whether the Pseudo- 
raelaniidse had not furnished two parallel branches, the one marine becoming extinct in the 
Tertiaries, the other fluviatile and related to the existing Melaniidse ” (‘ Manual,’ p. 697). 
