430 DR. HAXS SALFELD ON CERTAIN [Oct. I913,- 



half the length of the first ; it is directed a little obliquely, and is 

 likewise relatively broad. A ' suspensive ' lobe, which extends- 

 down to a radius drawn from the external lobe, possesses three 

 obliquely-directed auxiliary lobes. The saddles are more or Jess- 

 symmetrically divided by the primary indentations. The first 

 lateral saddle extends somewhat beyond the external saddle. 



The length of the body-chamber and the form of the aperture are- 

 not known. 



Locality. — Swindon, above the so-called 'Swindon Clay,' at the 

 base of the so-called ' Portland Oolite,' in the Lydite Pebble-Bed at 

 Eastlecott railway- cutting. 



Number of specimens studied. — Four. 



Collections. — Geological Institute of the University of Got- 

 tingen ; British Museum (Nat. Hist.), No. 88657. 



Remarks. — Perispliinctes eastlecott ensis stands near to P. id- 

 mensis Oppel sp., from the Gravesia Beds (lowest Portlandian), to 

 P. denseplicaius Waagen, and to P. postulmensis Blaschke. It is 

 distinguished from these species, however, by its different pro- 

 portions and its finer ribbing. In specimens having the same 

 width of umbilicus, P. eastlecottensis possesses a considerably 

 greater height and thickness of whorl. 



P. uhnensis Oppel sp., at given dimensions, has a wider umbilicus, 

 and possesses ribs which are stronger and broader and have a 

 marked backward slope ; in this species, also, the wider spacing of 

 the primary ribs comes on at a much earlier age. 



P. denseplicaius Waagen, from the Tithonian, and the very 

 imperfectly-known P. postulmensis Blaschke, stand nearer to the 

 English species than does P. ulmensis Oppel sp. P. denseplicatus 

 has a wider umbilicus, and is considerably thinner and narrower in 

 the whorl; also important differences in the lobe-line appear to 

 be present, at least so far as the material that has been figured- 

 is concerned. 



P. postulmensis appears likewise to have a wider umbilicus, and ; 

 to show narrower and thinner whorls. 



Virgatites quenstedti Rouillier is a form which has similar rib- 

 bing; but its whorl-section and proportions are quite different. 



EXPLANATION OF PLATES XLI & XLII. 



Plate XLI. 



Portlandian, eastlecottensis zone. 



Perisphinctes eastlecottensis, sp. nov. Holotype. Lydite Pebble-Bed, Eastle- 

 cott, Swindon (Wiltshire). Coll. British Museum (Nat. Hist.), No. 88657. 

 Side view, X07. 



Plate XLII. 

 Portlandian, eastlecottensis zone. 



Perisphinctes eastlecottensis, sp. nov. Fig. 1, peripheral view; Fig. 2, 

 apertural view of the example shown in PL XLI, both X 07. 



