•/ 



304 L. Agassiz on the Echhwdermata. 



(Echinon. scut., Munst.) — F. snffolciensis, Leach. — F. cranioluris, Linn., 

 Gmel. — F. ovulum, Lam. 



9. Echinoneus, V. Phels. and Lam. (Echinanaus, Keen. — Echi- 

 noconus, Breyn.) — Disc oval, more or less flattened ; ambulacra con- 

 verging uniformly towards the summit ; anus between the mouth 

 and posterior margin. All the species are living. 



E. cyclostomus, Lam. — E. semilunaris, Lam. — E. gibbosus, Lam. 



10. Eciiinolampas, Gray. (Echinanthus, Leske. — Clypeaster and 

 Galerites, Lam.) — Disc oval or circular; front margin more or less 



^ sloped ; ambulacra very large at the summit, where they form a 



star, the rays of which touch one another, but which gradually be- 

 come more narrow towards the periphery ; anus marginal, inferior. 

 There are some fossil species from the jura, the chalk, and tertiary 

 deposits, and one living. 



E.pentagonalis, Ag. (Clyp.pentag., Phil.) — E.fornicatus, Ag. (Clyp. forn., 

 Gold/.) — E. globosus, Ag. (Gal. glob., Defr.) — E. Kamigii, Gr. — E.Les- 

 hei, Ag. (Clyp. Lesk., Gold/.) — E. Montmollini, Ag. — E. productus, Ag. — 

 E. minor, Ag. — E. affinis, Ag. (Clyp. aff., Gold/.) — E. Bouei, Ag. (Clyp. 

 Bouei, Munst.) — E. Brongniarti, Ag. (Clyp. Brongn., Munst.) — E. conoideus, 

 Ag. (Clyp. conoid., Gold/.) — E. Cuvieri, Ag. (Clyp. Cuv., Munst.) — E. el- 

 lijjticm, Ag. (Clyp. ellipt., Munst.) — E. hemisphcericus, Ag. (Clyp. hemisph , 

 Lam.)—E. Klcinii, Ag. (Clyp. Klein., Goldf.)—E. Linkii, Ag. (Clyp. Link., 

 Goldf.) — E.polilus, Ag. (Clyp. poll., Lam.) — E. stelliferus, Ag. (Clyp. stel- 

 lif., Lam.) — E. subcylindricus, Ag. (Clyp. subcyl., Munst.) — E. trilobus, Ag. 

 (Clyp. tril., Defr.) — E. orienfalis, Gr. 



11. Clypeaster, Lam. (Echinantkus, Breyn. and Gr.) — Echino- 

 dorum and Echinodiscus, V. Phils. — (Lagana, Gr. and De Bl.) — Disc 



/ oval or subpentangular ; ambulacra forming at the summit a large 

 star, the rays of which are rounded at their extremity ; anus inferior 

 and marginal. The internal cavity is divided into chambers by ver- 

 tical pillars. The shell is very thick. There are several fossil spe- 

 cies from the tertiary deposits, and some living. 



CI. marginatus, Lam. — CI. alius, Lam. — CI. Gaymardi, Al. Br. — CI. Ri- 

 chard?, Desm. — CI. rosaceus, Lam. — CI. subdepressus, Ag. (Echinantlius 

 subdepr., Gr.)—Cl. ambigenus, De Bl. — CI. scutiformis, Lam. 



12. Echinarachnius, Leske and Gr. (Arachnoides, Kl. — Echino- 

 discus and Lagana, De Bl. — Scutclla, Lam.) — Disc circular or sub- 



J angular ; ambulacra as in Clypeaster, from which this genus espe- 



cially differs by the much flattened form of the shell, and by its thin 

 margins ; anus marginal. There is one fossil species from the ter- 

 tiary beds, and several living. 



E. lenticularis, Gr. — E. placenta, Gr. (Scut, plac, Lam.) — E. Parma, Gr. 



