OF SOUTHEFN INDIA. 
25 
Dc SOI* proposed to separate the family into tlirce suh-divisions, which appear 
to require some alterations. The CAUATomxi should, I think, he entu-ely excluded 
and form a special section of Ecuixoxeidm, or a separate family. The remaining 
genera might he classed in three sidj-families. 
1. CASSiDULiNM, with thc anal o])cning situated in an upper or terminal, 
more or less distinctly pronounced depression, generally of a somewhat larger size 
than the anus itself. The characteristic genera arc Casskltclus, Echinohrissus, 
Catopygus. 
2. EcmxozAMrixjB, with thc anus situated inferimly, more or loss close to the 
posterior end, and with the margins simple, sometimes slightly sloping, hut without 
any special depression. Echinolampos, Conochjpeus. 
3. ciAViASTRixjE, with thc apex of thc test somewdiat elevated, the pores in the 
anterior impair ambulacrum somewhat dilferent from those of the rest, generally 
smaller, and •u'ith the anus situated interiorly sub-marginal. 
The first and second sub-families arc considei’cd by Dr. Wright to form distinct 
families, under thc names EcnixoBRissin.E and Ecitixoiampw^e, hut judging from 
the variable position of the anal opening in other families, as, for instance, in 
the Ecuixocoxidje and EcnixoxEiDZE, I scarcely tliink that the character should 
receive primary importance in point of classification. 
The Cassibulilje arc known from the Jurassic period up to the present time, but 
the number of recent species is not very great; the maximum of development falls 
in the cretaceous period. 
In the South Indian deposits the first sub-family, or thc cassieulixje, is the only 
one represented, namely, by five different genera : Calopygus, Eotriopygus, Stiymato- 
pygus, Nucleolites, each with one, and Cassklulus with five species. 
V. CATOPYGUS, Agassiz, 1831. 
Test of medium size, generally sub-cylindrically ovate, moderately elevated, pos- 
teriorly nearly vertically truncated, often with a slight projection above the anus, 
which is situated at the upper end of the truncation ; below flattened, surface very 
finely tuherculated ; mouth and apex generally excentric, the former pentagonal, or 
nearly so, surrounded by five lobes, the latter composed of four perforated genital 
and five very small ocular plates ; ambulacra sub-petaloid, pores distinctly yoked. 
The peculiar more or less cylindrical shape of the test easily separates this genus 
from all other Cassieulidje, except Oolopygus, which merely differs by having the 
pores of the ambulacra not yoked. 
Until very recently all the Catopygi known were from ci’etaceous deposits, of 
wUich formation the genus was considered to be particularly cbaracteristic. The 
exception refers to a species, C. elegans, described by Laube from tertiary deposits 
of the Murray Cliffs in Australia, (comp. Sitzb. Akad. Wien, Math, Nat. Klasse, 
vol. lix, pt. i, 1869, p. 190). 
( 95 ) 
