260 
It differs not only by its greater relative length, wliicli autliorises me to class 
it Avitli Murchisonia, but also by the smallness of its spiral angle, and above 
all by the triple keel of its wborls, P. Morrisiana having only a double keel. 
Probably it was this triple keel, very well observed and figured by Dana, 
wliicli suggested to him the name under wbicli be first described it, and 
wliicli I have adopted. In shape this species resembles my 31. Verneuillimia, 
wbicli differs by having only a double keel occupy in g the middle of the 
spiral wborls, instead of following the suture as in 31. trifilata. 
Horizon and Localities. — Mr. Clarke sent me a block of greenish, 
calcareous sandstone, from Harper’s Hill, full of specimens of this species. 
Dana’s s^iecimen came from the same locality, while McCoy’s came from 
Muree and Wollongong — beds in wbicli I have found no trace of them. 
MuRCnisoNiA VERNEiTiLiANA, L. G. dc Koninch} 
PI. XXIII, Fig. 15. 
3Lurchisonia T^erne^uliana, L. G. de Koninck, 1811, Descr. Auim. Foss. Terr. Garb. Belg- 
p. 411, pi. 38, fig. 5. 
This shell is elongated and conical, and composed of seven to ten spiral 
wborls. The spire is divided nearly in the middle by a small, double, rather 
narrow, and slightly grooved keel, limiting the band or the sinus. On both 
sides of the band the spire is nearly flat, except the upper part of the last 
whorl which is convex. The surface is covered with flue, irregular, slightly 
oblique lines of growth. The suture is deep ; the columella simple, and only 
slightly sinuous ; and the aperture elongated and subrhomboidal. 
Limensions. — Althoucrh this shell can reach a length of about three 
centimetres, the Australian specimens are scarcely a third that length, and 
their diameter is only seven millimetres. The spiral angle is forty-one 
degrees. 
Lelations and Lifferences . — This species was considered by E. de 
Verneuil identical with the species from Paffrath, that he described under 
the name 3L. angnlata ; but it must not be confounded with another species 
to which Phillips has given the same name. It differs from it by its small size 
and its mueh greater spiral angle. It follows from this last characteristic that 
^ [In the original there are two Figs. 15. That of Murchisonia VerneuUiana is placed between Eigs. 7 
and 23. ~ W.S.D.] 
