IN THE ANGLO-PARIS BASIN 151 



Spath referred the paratypes of A. osmingtonensis to A. mimetictis. However, 

 the type of A. mimeticus (BMNH. C 30535, 1925 ; 131, pi. 11, figs. 7a, b) shows that 

 the inner whorls are strongly costate with well developed umbilical bullae quite 

 unlike A. osmingtonensis and in fact probably does not belong to Anahoplites at all. 

 The stratigraphical horizon of the Holotype of A. mimeticus has been discussed 

 above (p. 47), and it is not considered here to belong to the mammillatum Zone genus 

 Anahoplitoides (Casey 1966 ; 547-8). 



Horizon & localities. A. osmingtonensis occurs at the extreme top of the spathi 

 Subzone both in the Osmington area of Dorset, and the Petersfield area, Hampshire 

 (BMNH. C 35483). It is also present in the condensed spathi, intermedins Subzones 

 assemblage of Bed 4 at the Carriere Binot, St. Florentin (Yonne), and also at 

 Escragnolles (Alpes Maritimes) . 



Anahoplites grimsdalei sp. nov. 

 (PI. 1, figs. 2a, b) 



Derivation of name. After Mr. T. F. Grimsdale. 



Diagnosis. Anahoplites of the intermedins group ; discoidal, compressed, evolute. 

 Umbilical wall rounded, marked at margin by 20 comma-shaped bullae on outer 

 complete whorl. Each bulla gives rise to primary rib which bifurcates either just 

 above it or near middle of whorl flank. Ribs sickle-shaped, faint on inner whorls 

 terminating at ventro-lateral margins in distinct clavi arranged en-echelon each side of 

 tabulate slightly sulcate venter. Occasional short intercalated ribs stem from 

 primary ribs, one for each primary, on ventro-lateral shoulder to end at ventro- 

 lateral margin in intercalated clavi. Suture fine as in A . intermedins. 



Type material. Holotype BMNH. C 31702 (Lt. Col. R. H. Cunnington Coll.) 

 Uppermost spathi Subzone, between Osmington Mills and Black Head, Dorset. 



Dimensions. 93 -40 -20 -30 (slightly crushed laterally) 



Remarks. This species differs from A . evolutus of the basal part of the intermedins 

 Subzone, to which it is closely related, by possessing fainter and more distant ribbing 

 but which are more regularly bifurcating. Although the Holotype is slightly crushed 

 it is probably more compressed than A. evolutus. The short intercalated ribs on the 

 ventro-lateral shoulders, absent in A. evolutus, are reminiscent of those seen in the 

 much later Semenovites gracilis (Spath) of the varicosum Subzone (Upper Albian). 

 These are taken to an extreme development in a form which occurs in the basal part 

 of the intermedins Subzone at Caen Hill, Devizes (Bed 7) . Nonetheless, A . grimsdalei 

 in fact links A. osmingtonensis and A. evolutus. 



Horizon and locality. Extreme top of the spathi Subzone in the Osmington 

 area of Dorset, and at Petersfield, Hampshire (BMNH. C. 35482). 



