OP SOUTHERN INDIA. 
47 
Family, — CIDARIFjE. 
CidaridcB atiffustislellatce, auctoruiii. 
The CiDARiDM have generally a rotiform test, vith a large opening for tlie 
apical apparatus, a moderately sized anal and large oral opening, the latter round 
or somewhat angular, hut without any incisions ; the buccal membrane is scaly and 
the poriferous zones continue on it ; they are straight or slightly undulating ; in 
each series the pores arc generally in simple pairs. The ambulacra are very 
narrow, provided only with granules, Imt never with primary tubercles, of which 
(with a single exception) two roAvs occur on each intcrambulacral area ; they are 
perforated, surrounded by a distinctly developed areola, the edge of which is very 
often provided with a row of more or less distinctly mammillatcd secondary tubercles 
or granules, which are larger than those on the rest of the surface of each plate. The 
apical apparatus consists of tiA^e genital and five ocular plates, the right anterior of 
the former plates possessing, as usually, madreporiform structure. 
The form of the spines is very A^ariable, from cylindrical or fusiform to club- 
shaped or flattened ; they are longitudinally striated, and often granular or spinose ; 
the amount and details of ornamentation appear, however, to be subjected to con- 
siderable variation not only in the different species, but also in different stages of 
age of the same species, and even on different portions of the same shell. 
The members of this family, which occur both fossil and recent, are readily dis- 
tinguished from the other divisions of the Echinoidea endocyclica by the very narrow 
ambulacra, devoid of primary tubercles, and by the entire margin of the aperture. 
Cotteau classifies the Gidaridm in tw’o groups, the first with eight genera 
comprising the typical forms of the family, with only two rows of primary tuber- 
cles on each intcrambulacral area, and the second with the solitary genus Eetero- 
cidaris, an oolitic form, with more than two row^s of tubercles on the same area. We 
have in South India only the genus Cklaris represented, and although four or five 
different species are indicated, none is unfortunatelj^ in a state of preservation which 
Avould permit of a thoroughly satisfactory specific definition, but several appear to be 
identical wTth known European species. 
XVI. CIDARIS, Klein, 1734. 
Test subcircular, more or less elevated and depressed from above and below, 
ambulacra nearly straight, with tw’o or more roAVS of granules ; poriferous zones 
narrow, subflexuous, the pores in each pair usually separated by a granular swell- 
ing ; interambulacra with large, perforated or not perforated, primary tubercles. 
Apical disc subpentagonal or rounded, with a pentagonal anal opening ; aperture 
large, rounded ; spines very variable in shape, ridged or granular. 
The genus Cklaris extends from the Trias (if not from the carboniferous) 
through all the successive formations, and is CA’cn in the present seas numerously 
represented. In South India the foUoAA'iug species are indicated. 
N 
( 117 ) 
