TF. H. Rudleston — On the Torlishire Oolites. 153 



81.— Pleurotomaria guttata, Phillips, 1829. Plate IV. Figs. 



3, 3a, and 4. 

 1829, 1835. TrocJms guttatits, Phillips, G. Y. p. 112, pi. vi. %. 14. K.E. 

 1849. Pleurotomaria guttata, WOrliignj. Prod. 1. p. 333. Et. Cal. 

 1854. Trochns guttatus, Phil. Morris, Cat. p. 281. 

 1859. Pleurotomaria arenosa, Leckenby, Q.J.G.S. 1859, p. 12, pi. 3, fig. 1. 



1875. pj- JJ!"^^^' J^)^ } as distinct species. Phillips, G. T. 3rd ed. p. 259. 

 Compare also — 



Pleurotomaria cincta (Miinst), D'Orb., T. J. p. 560, pi. 420. 



,, galatheo, D'Orbigny, T. J. p. 566, pi. 423, figs 1-4. 



,, clathrata, Miinst. Goldf. Pet. 3, p. 71, plate 186, fig. 8. 



Bibliograpliy, etc. — I liave not seen the type of Trochus guttatus, 

 which belonged to Williamson, and should be in the Scarborough. 

 Museum. Phillips's figure is fairly characteristic, and shows the 

 crenulated girdle very clearly. Our Figure 4 represents a fossil in a 

 somewhat similar condition. D'Orbigny recognized Phillips's species 

 as a Pleurotomaria, though Morris did not seem to have been satisfied 

 on this point, probably because of the apparent want of the band of 

 the sinus (slit-band). We cannot wonder that, when Mr. Leckenby 

 obtained such a beautiful fragment as is depicted in our Figure 3, he 

 should have fancied he had found a new species (P/. arenosa). 



The difierence between PI. guttata and PL arenosa seems to have 

 been accepted by Phillips without question in his last edition. Yet 

 it is evident that Mr. Leckenby finally regarded them as synonymous. 

 The following note in the Woodwardian Museum testifies to this — 

 " Under the title P. arenosa I have unfortunately described in my 

 paper on the Kelloway Rock in the Geol. Journ. Feb. 1859, a speci- 

 men then in Bean's Collection, now in the British Museum, which on 

 a subsequent examination of Phillips's Trochus guttatus in the Scar- 

 borough Museum, I find to be only a more perfect condition of the 

 latter shell. 



" Phillips's figure is that of partial cast, the only portion of the 

 shell preserved being a thickened band at the suture." 



Descriptions. — Specimen from the Kelloway Eock (zone 5), Scar- 

 borough. Leckenby Collection. Fig. 4. 



Height 30 millimetres. 



Width 40 



^ " ^ Mean spiral angle 89°. 



Eatio of body-whorl to entire height . . 50 : 100. 



Shell conical, trochoid, much wider than high, moderately (?) 

 umbiiicated. The angle of the spire is slightly concave, so that 

 between the opening of the spiral angle and the mean spiral angle 

 there is a difference of some degrees. Number of whorls about 8, 

 tapering to a sharp apex : the whorls are nearly flat, and their 

 inclination about the same as the mean angle of the spire. 



The ornaments consist of tolerably close spiral lines, which are 

 decussated by axial lines, and more so in the posterior than in the 

 anterior region. The base of each whorl is distinguished V)y a hand- 

 some crenulated girdle : just above this lies the band of the sinus 

 (slit-baud), which is narrow and projects slightly from the general 



