from the Island of Malta. Ill 



Agass.j EchinocyamuSy Van Phels., Fibularia, Lamk., Lenita, 

 Desor. 



Genus Clypeaster (Lamarck, 1816). 



Form oval, inclining to pentagonal, rostrated before, truncated 

 behind ; upper surface more or less inflated, sometimes campa- 

 nulate, conical or subconical ; inferior surface flat, always concave 

 around the mouth, with five straight simple ambulacral furrows 

 proceeding from the angles of the mouth to the border; the 

 dorsal portion of the ambulacral largely petaloid, greatly exceed- 

 ing the interambulacra in size, and forming elegant leaf-like 

 expansions, in general convex, arched, and prominent ; bounded 

 on each side by large poriferous zones, the pores of which are 

 wide apart and united by transverse sulci ; the apical disc formed 

 of five genital plates at the summits of the interambulacra, with 

 five ocular plates alternating with them ; in the centre of this 

 circle is the spongy madreporiform body, of a pentagonal figure : 

 tubercles uniform in size and very numerous, equally distributed 

 over the test; summits perforated, and surrounded by very 

 deep areolas ; mouth symmetrical, central, pentagonal, lodged in 

 a concave depression in the middle of the base; auricles composed 

 of ten distinct auricular processes set in pairs : the jaws form 

 a pentagonal pyramid, composed of ten separate pieces, trun- 

 cated at the summit, which is bordered by a subcircular band ; 

 teeth five, large, and bent : anus small, round, and inframar- 

 ginal : interior of the test with a number of pillar-like processes 

 towards the border. All the species of this genus live in the 

 seas of warm latitudes, or are found fossil in the tertiary rocks 

 only. We have six living and twelve fossil species. 



Clypeaster altus, Leske, sp. 



Syn. Echinus e Melita, Seilla, Corp. Mar. pi. 9. figs. 1, 2. 

 Echinanthus altusy Leske, Klein, Echinoderm. apud Leske, No. 48. 



p. 189.pl. 53. fig. 4. 

 Echinus alius, Gmelin, Linne by Turton, vol. iv. p. 149. 

 Clypeaster alius, Lamarck, Hist. Nat. des Animaux sans Vertebras, 



2nd ed. tom. iii. p. 290 ; Deslongchamps, Encycl. t. ii. p. 199 ; 



Defrance, Diet. So. Nat. t. ix. p. 449 ; Blainville, Man. d'Actin. 



p. 216; Desmoulins, Echinides, no. 7. p. 216; Agassiz and 



Desor, Cat. rais., Ann. So. Nat. tom. vii. p. 130; Sismonda, 



Ech. Foss. Nizza, p. 46 ; Ech. Foss. Piem. p. 40 ; Grateloup, 



Mem. Foss. Oursins de Dax, p. 41. 



Test oblong ; anterior border convex ; lateral borders undulated ; 

 posterior border squarely truncated ; marginal fold more or 

 less thickened ; dorsal surface elevated into a dome shape ; 

 vertex nearly central ; ambulacral areas largely petaloid, their 

 base extending nearly to the margin : base flat ; mouth large 



