INTRODUCTION. 
The Actinozoa, wliich form a separate sub-kingdom,- characterized by having 
their organs disposed in radii which are four, five, six, or a multiple of these numbers, 
and by possessing a special opening leading to a digestive cavity,- are represented 
in the South Indian cretaceous deposits by two classes, the Echinodermata and the 
Corals, or Antliozoa, the former of which are the subject of the present article. 
Few other classes of animals can compete with the Echinodermata in the 
zoological and geological interest which attaches to their study. The intimate 
relation, which exists between the soft and the solid parts of the animal, makes them 
particularly fit for tracing out the gradual changes which have taken place in the 
development of the class in successive periods up to the present time. Of course, tlie 
short monograph here given cannot be of any very great importance in regard to 
this general subject, but it has its little value in making us acquainted Avith the 
remains of al)out twenty-three new species, in addition to a few others Avhich had 
been already described by the late Prof. Forbes and M. E’Orbigny, and in aid- 
ing to define the age of the different upper cretaceous beds in the Trichinopoly and 
South Arcot Districts of South India. 
( 89 ) 
