6 



BKITISH FOSSILS. 



to Galerites umbrella still being retained for a French species 

 of Pygaster, while the P. umbrella of the Ech. Suisses is altered 

 to P. dilatatus. No mention is made of the P. semisulcatus of 

 Phillips. 



Dr. Wright, Annals Nat. Hist, for 1852, gave the first real des- 

 cription of the British species, distinguishing it carefully from the 

 two other British forms, while with good reason expressing doubts 

 as to its identity with the Swiss species, of which only a cast was 

 published. In Morris's Catalogue, second edition, Professor E. Forbes 

 adopted the present name, quoting Agassiz's P. itmbrella only as a 

 synonym. This course we are bound to follow in this Decade, for 

 even if Agassiz's species should prove identical, it will be necessary 

 to keep Phillips' name, since the old reference to Lamarck is un- 

 doubtedly erroneous. 



Locality and Range. — Great . Oolite, Minchinhampton, Glou- 

 cestershire (Dr. Wright) ; Whitwell, Yorkshire, (in Calc. Grit 

 Phillips), but probably, "GREAT Oolite" (Dr. Wright). See note at 

 end of next description. Inferior Oolite, Crickley Hill and Chel- 

 tenham, in the " Pea Grit," (Id. and Coll. Geol. Survey.) 



Foreign Distribution — doubtful. If P. patelU/ormis (P. um- 

 brella of Agassiz) be identical, it occurs in the Kimmeridge Clay of 

 the Jura Soleurois. 



Explanation of Plate VII. 



Fig. 1. A fine specimen full grown, from the Inf. Oolite, Cheltenham, (Dr. Wright). 

 Fig. 2. Posterior view of do., showing the four rows of ambulacral tubercles towards 



the margin. 

 Fig. 3. Part of under side. 



Fig, 4. Plates and avenues, with pores in single file. 



Fig. 5, 6. Primary and secondary ambulacral tubercles, with the usual number of 



pores opposite to them. The pairs of pores are somewhat divergent. 

 Fig. 7. Interambulacral tubercle, with its surrounding granules. 



Fig. 8. Side view of the same. The area is scarcely sunk enough round the margin, 

 in this figure, 



J. W. Salter. 



March 1856. 



