Yol. 63.] AMBERLEYA AND SPIRORBIS. 435 



I do not seem to have figured anything exactly corresponding to this form 

 from the Inferior Oolite. It differs from the Duudry type, and might almost 

 constitute a distinct species.' 



I dedicate this species to Mr. Hudleston, who has contributed so 

 materially to our knowledge of the Inferior-Oolite Gasteropoda of 

 this countr} T . 



I have also collected this species from the bottom-beds of the 

 Clypeus-Grit of Rodborough Hill, near Stroud. 



Spirorbis midfordensis, sp. nov. (Fig. 7.) 



T.l. Eoad-section, Midford, near Bath. 

 H. Upper Coral-Bed. 

 rj. Truellii. 

 Colin. L. Kichardson. 



Diagnosis. — Tube minute, twice spirally enrolled ; flat on the 



side by which it was attached ; 

 Fig. 7.— Spirorbis midfordensis, externally ornamented with 

 sp. nov. {Magnified about wavv longitudinal linea3 (which 

 15 diameters.) are ften worn off, leaving the 



/ ; ; ; ; |\ ,.<~-^ shell-surface smooth), and in the 



§^. region of the aperture often 

 % exhibiting several coarse folds, 

 ■A which are most divergent on the 

 if periphery. The aperture is sub- 

 $w pentagonal, but more angular in 

 "^ ■•--_ 1 some specimens than in others. 



Re marks. — This Spirorbis is 

 very characteristic of the Upper 

 Coral-Bed, where it occurs in 

 great numbers. Mr. Charles 

 Upton has obtained it from this 

 * ■:.;( bed at Midford, and at "Wor- 



x v) gan's Quarry, near Stroud ; and 



Mr. E. Talbot Paris showed me a 

 dwarfed Pseudoglossothyris sim- 

 plex, from the Pea-Grit of Crickley Hill, with a number of 

 specimens of the Spirorbis adhering to it. 



Sjnrorbis midfordensis closely resembles Serpula valvata, Gold- 

 fuss, from the Muschelkalk, but is separable therefrom by its usually 

 more angular mouth and by its surface-ornamentation. 



EXPLANATION OF PLATES XXVIII & XXIX. 



[All the figures, except 6 d in PL XXVIII, are of the natural size.] 



Plate XXVIII. 



Figs. 1 a-1 g. Acanthothyris doultingensis, sp. nov. (See p. 426.) 



1 a= dorsal view; 1 6=lateral view; 1 c= anterior view. 

 Horizon: Fullers' Earth, Bathonian. Locality : Farmcombe 

 Quarry, near Doulting. Colin.: L. Kichardson. 



