CATALOGUE OF ECHINIDA, 
10 
7. Leodia. 
Body depressed, with, a posterior, and five perforations be- 
tween the end of the ambulacra and edge ; the marginal 
ambulacral tesserae square, like the inter-ambulacral ones ; 
ambulacra lanceolate, acute at the tip, the anterior one most 
narrow and longest ; pores united by a groove ; ovarial plate 
pentangular ; ovarial pores three ; oral grooves slightly im- 
pressed, converging towards the margin, in front of the ambu- 
k lacral perforations, simply forked at the end ; vent near the 
mouth, in front of the anal perforations, with a group of three 
or four larger spines between it and the mouth. 
Leodia, Gray, Pro. Zool. jSoc. 1851. 
1. Leodia Richardsonii. 
Body sub-orbicular, depressed, slightly five-lobed, hinder 
edge transverse ; ambulacra lanceolate, not reaching to the 
discal perforations ; discal perforation ovate, small, the ante- 
rior smallest, the posterior longest, with two pair of rather 
large tesserae between the ends of the ambulacra and the 
foramens, the upper pair sub-trigOnal. 
Leodia Richardsonii, Gray , Pro. Zool. Soc. 1851. 
Hab. West Indies. 
a. Small, very flat, rather deformed ; the right side various, 
with the perforations of that side nearly obliterated. 
West Indies. Presented by Sir John Richardson, M.D. 
a. Ambulacral petals broad , closed at the end. 
8. Echinodiscus. 
Shell flat, subcircular, with a slit or holes in the hinder part 
of the two hinder ambulacral areas ; ambulacral petals closed ; 
inferior ambulacral grooves waved, or slightly branched ; mouth 
small ; jaws flat ; vent inferior, more or less far from the edge ; 
ovarial pores four, contiguous to the madreporiform body. 
The recent species have two linear holes, the fossils (Am- 
phiope, Agassiz) have two round ones, and another fossil 
(Monophora) a single elongate slit. 
Lobophora. Agassiz, Mon. Echin. ii. 62, 147 ; Agassiz & Desor , 
Ann. Sci. Nat. 1847, 136. 
Scutella, § 1, b., Eschsch. Zool. Atlas, 19. 
Mellita, sp., Klein ap. LesJce , 25. 
Placenta, sp., Klein. 
Echinodiscus, sp., Leske ap. Klein,- 196 ; Knorr — Muller , 
Echinodiscus, § 3 ; Gray, Ann. Phil. 1825, 6, 
Echinogly'cus, Van Phelsum , 34. 
