54 W. H. Sudleston—On the Yorhshire Oolites. 



Description of another variety near to M. oviilata, H. and D. 

 From the same horizon and locality. Leckenby Coll. Figs. 6 & 6a. 



Height 7'5 millimetres. 



Width 10 



Spiral angle 112°. 



itatio of body-whorl to entire shell 86 : 100. 



Shell small, transversely ovate, depressed, not umbilicated. The 

 spire is few-whorled and bears but a small proportion to the body- 

 whorl, which is slightly flattened in its upper part, and extremely 

 swollen anteriorly. Suture almost invisible, whorls extremely 

 smooth. Aperture transversely (to the axis) ovate, columella short, 

 thick and toothed anteriorly. 



Relations and Distribution. — This is the most rotelliform of the 

 M. Icevigata group in the Yorkshire Dogger, and is to a certain ex- 

 tent the representative of Monodonta ovulata, Heb. et Desl. The 

 typical M. Icevigata lies between the two extremes shown in Figures 

 4 and 6. Extremely rare in the Yorkshire Dogger. 



As regards the Kelations and Distribution of the M. IcBvigata 

 group generally, this subject was partly discussed under the heading 

 " Bibliographj^" It might be hazardous to speculate how nearly 

 some of the small smooth Turbos, not unfrequent in the Lias, are re- 

 lated to our Turbo [Monodonta) Icevigatus group. This will require 

 further investigation. As regards distribution in the Lower Oolites, 

 we find all three sections recognized by Laube from the Brown Jura 

 of Balin, though his identifications are not absolutely correct. By 

 this author the group is referred to Chrysostoma, Swainson, classed 

 by Gray with the rotelliform Trochids. Not noticed by Brauns in 

 the Middle Jura of N. W. Germany. In the Yorkshire Oolites we 

 do not find any shells of this kind between the Dogger and the Coral 

 Eag, where three species were recognized (see " Corallian Gastero- 

 poda," Geol. Mag. 1881, p. 53), in many respects analogous to the 

 three sections of Turbo Icevigatus. 



69.— TuEBo (Delphinula) funiculatus, Phillips, 1829. Varieties. 

 Plate IL Figs. 7 and 8. 



See " Corallian Gasteropoda," (Geol. Mag. 1881, p. 54.) 



Compare also 

 Turbo Hamptonensis, Morris and Lycett, Gt. Ool. Moll. p. 64, pi. ix. fig. 30. 

 Turbo Davoustii, D'Orbigny, Terr. Jurass. p. 344, pi. 331, figs. 7-10. 



Bibliography, etc. — The type is, of course, a Corallian fossil not 

 uncommon in the Coral Eag of Yorkshire. The fossils now under 

 consideration are representative rather than identical forms ; though, 

 after all, the principal difference is probably due to the more 

 exuberant development of the Coral Rag fossil and partly to difference 

 of status. As these shells are extremely rare in the Lower Oolites of 

 Yorkshire, the present classification is only provisional, and the same 

 may be said of the suggested comparisons.^ 



' In both figures, but especially in Figure 8, the granulations are made too small 

 and too circular. There are indications that these nodes were more imbricated. 



