300 MRS. JANE LONGSTAFF ON SOME NEW [Sept. I9I2, 



the keel and the thread above is suggestive of a sinual band, and 

 it was mistaken for such by M'Coy ; the lines of growth, however, 

 pass over unbroken with very slight deflection, showing clearly that 

 there was no sinus or slit in this position. Though none of the 

 specimens of this species with which I am acquainted are preserved 

 in such a manner as to exhibit a structure underlying the keel similar 

 to that existing in Tr. grifitM, I consider it advisable to group the 

 two species together at present, since their general characteristics 

 are very similar. The discovery of further details, not only of 

 the keel but also of the inner lip, may, however, prove them to be 

 distinct — so far the form of the latter is unknown in Tr. griffithi. 



Dimensions. — The largest specimen met with is that in the 

 Sedgwick Museum (PI. XXVIII, fig. 1): the apex is broken, and 

 the five remaining whorls measure Q'2 centimetres in length; the 

 greatest width seen is 6*5 cm. : it must really be greater than this, 

 but the aperture is embedded. The shell (PI . XXYIII, figs. 2a-2c) 

 in Dr. Trechmann's collection is remarkable for having the inner 

 lip preserved, and is therefore chosen as the holotype. The apex 

 is broken, and only three whorls remain : these have a length of 

 b-b cm. and a maximum width of 4'8 cm. Another example in the 

 same collection, of which the apex is also imperfect, has five whorls 

 in a length of 4'4 centimetres. 



Localities and horizon. — The specimen in the Sedgwick 

 Museum is from the Lower Carboniferous Limestone of Lowick. 

 Two in Dr. Trechmann's collection are from the Great Limestone 

 at Stanhope-in-Weardale. 



Pamily Pleurotomariidae d'Orb. 



Genus Pletjrotomaeia Def ranee : Subgenus Pooedella, nov. 



Diagnosis. — Shell turbinate, composed of numerous convex 

 and smooth whorls. Spire somewhat elevated. Band submedian ; 

 lines of growth curving very obliquely backwards to it above, and 

 forward from it below. Aperture subcircular. Xo umbilicus. 

 Test thin. 



G e n 1 y p e. — Foordella Jiihernica, 



Dimensions. — Length = from about 4'5 to 7*5 centimetres. 



Remarks and resemblances. — In my paper in this Journal 

 vol. li (1895) p. 231, I erroneously identified species of this 

 subgenus from Ireland with Caliendrum vittatum (Phill.), all the 

 Irish specimens that I had then seen being very imperfect. After 

 the examination of better-preserved examples I feel convinced that 

 not only are they distinct species, but that they also constitute a 

 new subgenus. It is distinguished from Caliendrum Brown by 

 its shorter and broader form, the spiral angle being from 60° to 65°, 

 whereas that of the latter genus is from 50° to bb° ; by its more 

 oblique lines of growth; and by its aperture being more nearly 

 circular. It difi'ers from PtycJiomj[)Tialina Bayle, Mourlonia De Kon., 

 and Eurijzone Koken, in the higher position of the band, and from 



