GENEEA AND GROUPS OF THE ECHINOIDEl. 257 



Genus Gtjaltieeia, Desor, 1847, Catal. Rais., Ann d. Sci. Nat. 

 vol. viii. p. 10. Desor, 1858, Synopsis, p. 406. Cotteau^ 

 1884, Ech. de Saint Palais, p. 32, Ann. d. Sc. Geol. vol. xvi. 

 p]. vi. 



Test moderate in size, ovoid elliptical in marginal outline, 

 rounded in front, without a deep groove, slightly narrower behiud 

 and truncated, very tumid but low dorsally, flat actinally except 

 behind the peristome, where there is some convexity. 



Apical system pentagonal, with four basal plates, each with 

 a large pore ; the madreporite extending centrally, and separating 

 the postero-lateral basal plates, and also the posterior radial plates. 



Ambulacra diverse, the anterior in a slight depression abacti- 

 nally, broad, with the pairs of small pores arranged obliquely ; the 

 paired ambulacra long, flush, petaloid, tending to but not closing ; 

 the anterior poriferous zone of the antero-lateral pair with small 

 pores near the apex, elsewhere the poriferous zones broad; the 

 interporiferous area broad, and the whole flexuous ; the postero- 

 lateral ambulacra straighter, with the poriferous zones broad. 



Peristome transverse, broadly elliptical, with a narrow labrum 

 which is long, and has an amphisternura beyond ; peristomial 

 interradial plates of the antero-lateral areas tuberculate, and the 

 labrum also. The long posterior ambulacra and the anterior ambu- 

 lacrum are ornamented with raised irregular prominences. Peri- 

 proct posterior, high up, oval, longitudinal. 



A well-defined fasciole crosses all the ambulacra at the distance 

 of three quarters of their length from the apical system, without 

 interfering with the nature of the pairs of pores. An elliptical 

 bent subanal fasciole enclosing a broad area, 



Fossil. Eocene : Europe. 



Genus Linopisteustes, A. Agassiz, 1881 (subgenus), Heport on 

 the ' Challenger ' Echini, p. 167 ; 1883, ' Blalce ' Echini, 

 p. 62. 



Syn. PalcBopneustes, A. Ag. (pars). 



Test large, depressed, but rather subhemispherical abactinally, 

 the posterior part of the test sloping gradually ; oval in ambital 

 outline and notched in front, and may be slightly so posteriorly ; 

 flat actinally, with a low median keel behind the peristome. 



Apical system central or slightly excentric in front, with four 

 perforated basal plates ; the madreporite extending from the right 



LINN. JOUEN. — ZOOLOGY, YOL. XXIII, 17 



