180 Dr. T. Wright on some new species of Hemipedina. 
ten rows of tubercles at the equator, each tubercular plate hav- 
ing five tubercles abreast; areolas surrounded by circlets of 
small granules; spines slender, sculptured with longitudinal 
lines. 
Dimensions.—Transverse diameter 2,4, inches ? 
Locality.—Kimmeridge clay, Boulogne-sur-Mer. Collected 
by M. Bouchard Chantereaux. 
Coll. M. Bouchard Chantereaux at Boulogne. 
In the present state of our knowledge it would be premature 
to suggest subdivisions, but it is clear that, we have two distinct 
types in the genus Hemipedina: 1st, those with two rows of 
large tubercles, and a wide intertubercular granulated space in 
the middle of the interambulacral areas; and 2nd, those with 
four, six, eight or ten rows of nearly equal-sized tubercles in 
these areas at the equator. 
