184 PROCEEDINGS COTTESWOLD CLUB 1908 
APPENDIX TI. 
AN ARTIFICIAL KEY. TO THE GENEK@ 
BY 
E. TALBOT PARIS 
A purely artificial key to the genera of Inferior-Oolite 
echinoids is appended, to enable the genera to be deter- 
mined with the minimum amount of trouble. Reference 
then to Table III. will show the species belonging to 
the various genera and the hemera in which they lived. 
This list is alphabetically arranged for convenience of 
reference. 7 
TABLE VI.—AN ARTIFICIAL KEY TO THE GENERA. 
(In the following key the abbreviation “Amb” and “Iamb” are used for 
‘‘Ambulacrum” and “Interambulacrum” respectively.) 
A. ANAL CANAL DEVELOPED. 
* Poriferous zones wide. 
Floscelle rudimentary or absent ans LEchinobrissus 
Floscelle present ae a She Clypeus [Except 
Clypeus A gassizi, 
in which the anal 
canal is only 
faintly marked. ] 
** Poriferous zones narrow. 
Apical system sub-circular ... £52 Galeropygus 
Apical system elongate Bae ea Hyboclypeus 
B. ANAL CANAL NOT DEVELOPED. 
* Anus situated inside the apical system, 
(i) Tubercles crenulate. 
a. Pores uniserial. 
Large Iamb tubercles; Ambs wavy con- 
taining two rows of granules sas Cidaris 
Large lamb tubercles; Ambs wavy or 
straight, with small tubercles at 
the base... ae ISG ie Hemicidaris 
Iamb tubercles the same size as amb 
tubercles... Pseudodiadema 
Iamb: tubercles larger than amb 
tubercles ; sur-anal plate present ... Acrosalenia 
