292 W. H. Hudleston—The Vorkshive Oolite. 
decussated by transverse bands in those portions of this shell which 
have been preserved. To be perfectly safe, however, similar parts 
only should be brought under comparison. 
2.—PurpPurRoIDEA cf. TUBEROSA, Sowerby, 1827. Pl. VIII. Figs. 3a. &6.. 
Murex tuberosus, Sowerby, 1827, Min. Conch., Tab. 578, fig. 4. 
Bibliography, etc.—As far as one can judge from Sowerby’s figure, 
he appears to have described one of the narrower forms of Pur- 
puroidea from the “Pisolite at Malton.” If we are to refer all the 
Yorkshire specimens to one specific designation, then Sowerby’s © 
name must take precedence of that given by Young and Bird. 
Description.—Specimen probably from the Coral Rag of Langton 
Wold (Leckenby Collection). 
Wenetby (restored) Sie nirekeg ate iene eee ice ae 69 millimétres. 
ip xtreme widthiqes sae rea eee Cee Cy 
Length of body-whorl to entire shell ........ 68: 100. 
Some MAD Sogn aoa coo G900 0000 50aN 000% 70°. 
The above measurements prove that there is an important differ- 
ence in the dimensions of this and the preceding species. The 
outline is rather more on the plan of the Minchinhampton species, 
but the ornaments are entirely distinct. The whorls were probably 
six in number: the first four are devoid of tubercles, but are 
marked by fine transverse lines (not shown in the figure). The 
penultimate whorl slopes outwards towards its keel, below which it 
falls away at the same angle as the upper whorls; the front part 
of this whorl gradually shows a moderate tuberculation, which 
increases with considerable regularity, and finally developes a very 
prominent tubercle or horn. The body-whorl, like that of the pre- 
ceding species, is divided into three areas. The uppermost area 
slopes outwards towards the principal keel. It is ornamented with 
transverse lines or ridges, having a tendency to arrange themselves 
in pairs, and is more or less decussated by longitudinal plications 
and lines. (This kind of minute ornamentation extends over the 
greater portion of the shell, producing a very pretty effect.) The 
upper or principal keel is moderately and regularly tuberculated, 
and finally, like the whorl above, developes one tubercle more 
prominent than the rest. ‘The second keel is well defined near the 
outer lip, and moderately nodular, but seems to die out when traced 
backwards. The anterior third of the body-whorl, as far as we can 
judge from what is left, appears to have had wavy ribs partially 
bifurcating from the nodes of the lower keel, though probably the 
shell became smoother as the columellar region was approached. 
The posterior part of the aperture is decidedly contracted, and 
is more like a Murex than is usual with the Purpuroids. The 
columellar lip is also more curved, and its general outline very 
different from P. nodulata. 
Relations and Distribution.—Neither of these two species of Pur- 
puroidea can be exactly matched elsewhere. P. Lapierrea, Buv., 
perhaps the nearest relation to P. nodulata, occurs in the ferruginous 
Oolite of Viel St.-Remy, which is about the horizon of the passage- 
beds of the Lower Calcareous Grit. Buvignier also quotes it from 
