H.L. Clark, 1923 : 392 H.L. Clark, 1925a : 149 H.L. Clark, 1924 : 10 Clark & Courtman-Stock, 1976 : 241 Schultz, 2009 : 539 Mortensen, 1948d : 94 Illustrated guide to the echinoid (Echinodermata: Echinoidea) fauna of South Africa Filander, Zoleka Griffiths, Charles Zootaxa 2017 4296 1 1 72 WDZR H. L. Clark, 1925 c H. L. Clark 1925 [151,661,1610,1636] Echinoidea Clypeasteridae Clypeaster Animalia Clypeasteroida 49 50 Echinodermata species eurychorius     Clypeaster humulis:  H.L. Clark, 1923: 392;  H.L. Clark, 1925a: 149.    Clypeaster eurychorius  H.L. Clark, 1924: 10–11. Pl. III;  Clark & Courtman-Stock, 1976: 241;  Schultz, 2009: 539, Figs 913– 916.    Clypeaster( Stolonclypus) eurychorius:  Mortensen, 1948d: 94–96. Pl. XXX, Fig. 2. Pl. XXXI, Figs 2, 3. Pl. XXXII, Fig. 3. Pl. XXXIII, Fig. 2.   Material examined.MBC-A 022261; MBC-A 022286; MBC-A 022290; MBC-A023306; A22330; A28431; A23092.  Identification.Distinguished from other  Clypeasterspecies within the region in having a rounded pentagonal test, flat except at elevated petal area, margin thick. Petals short, opened distally, pore-zones narrow, interporiferous zones wider. Primary tubercles sparse, miliaries smaller than primaries. Primary spines small, slender, longer towards mouth; miliaries slender, with thick tip. Preserved specimens brownish-green; denuded test uniformly yellowish-white.   Global maximum size.Maximum test length 145 mm.  Global distribution.South and East coast regions of South Africa, northward to Pemba Strait (Tanzania) and off Mauritius, at 125–320 mdepth ( Mortensen 1948d; Schultz 2009).   Remarks.Deep-water species, burrows in uppermost layer of sediment, where it feeds on organic particles.