from the Lias and OulUes. 165 



primary tubercles in the interambulacral areas^ aud deeper exca- 

 vated areolar spaces with a more elevated marginal rim around 

 them : these characters serve to distinguish C. Fowleri from 

 C. Bouchardii at a glance, and the same diagnostic traits separate 

 it from C. Edwardsii, nobis. 



Locality and stratigraphical range. — We have found this spe- 

 cies in the Pea-grit of the Inferior Oolite of Crickley, Leck- 

 hampton, and Birdlip Hills, Gloucestershire, but have never met 

 with any traces of it in the Upper Ragstone beds so rich in 

 Urchin forms. Some separate plates collected from the Bradford 

 clay near the Tetbury Road Station, Great Western Railway, 

 closely resemble this form ; but as no entire specimen, that we are 

 aware of, has been found, it is impossible to state whether it has 

 a wider range in the higher beds of the lower division of the 

 Oolites or not. 



We dedicate this species to our friend M. Bouchard Chautereaux 

 of Boulogne, to whom we are indebted for some beautiful and 

 i-are specimens of Echinoderms and other fossils from the rocks 

 of the Boulonnais, most kindly contributed by him to aid us in 

 the composition of these memoirs. 



Hemicxdaris minor, Agassiz. PI. XL fig.3, a-c. 



Syn, Hemicidaris minor, Agassiz, Catalogus Systematicus, p. 9 ; 



Agassiz and Desor's Catalogue ralsonne des Echinides, Annales 



des Sci. Nat. torn. vi. p. 339. 

 Acrosalenia rarispina, M'Cov, Ann. of Nat. Hist. 2nd Series, toL ii. 



p. 411. 



Test hemispherical above, flat at the base ; arabulacral areas 

 slightly iiexuous, not prominent, with six large tubercles at 

 their base, and four rows of small unequal-sized granules in 

 the middle, diminishing to two rows in the upper part of the 

 areas ; interambulacral areas three times the width of the am- 

 bulacral, with three primary tubercles on the upper surface 

 and three smaller ones at the base ; the wide intertubercular 

 spaces are covered with small distinct nearly equal- sized gra- 

 nules, which form complete circles around the margins of the 

 areolas of the primary tubercles ; the apical disc is of mode- 

 rate size, and its ovarial plates are covered with a delicate gra- 

 nulation ; base flat, mouth-opening large and decagonal ; 

 pores arranged in the avenues in a single file throughout. 



Height /(jths of an inch, transverse diameter /^ths of an inch. 



Description. — Tliis beautiful little Urchin was first discovered 

 in the etage Bathonien of Langrune, Calvados, the true equiva- 

 lent of the Great Oolite of English geologists ; it was entered 



