154 ECH1N0IDEA. 



X''. English Channel. Miss Bueldand. 



y". British Seas. Coll. Mantell. 



z'-d 3 . British Seas. 



6. Echinus elegans. (Plate XIV. figs. 3 & 4.) 



Echinus elegans, Dub. $ Eor. Vet.-Ak. Edlg. 1844 (1846), p. 272, 

 pi. x. figs. 40-42; Ag. 8f Desor, Ami. Sci, Nat. vi. (1846) p. 365; 

 Sars, Norg. Ech. (1861 ) p. 94 ; Duj. 8f Hupe, Hist. Nut. Ech. 

 (1862) p. 524 ; A. Ag. Rev. Ech. (1872-3) pp. 122 & 491, pi. vii. a. 

 fig. 4; Wyv. Thorns. Phil. Trans, clxiv. (1874) p. 744, pi. Ixviii. 

 figs. 11-13; Al. Ag. Bull. Mus. C. Z. viii. (1880) p. 77; id. Chall. 

 Rep. (1881) p. 115. 



Test rather stout and rather high, sloping somewhat rapidly 

 from apex to ambitus, flattened below. Primary spines of moderate 

 length, often with the appearance of being broken at their tips, 

 much shorter below than above the ambitus, red in colour, except 

 at the tip which is white ; below the ambitus as much as or more 

 than half the length of the spine may be white. Secondary spines 

 of the same colour, numerous, rather delicate. Pedicellariae nume- 

 rous, large, valves as much as 2*5 mm. long. Spines proportionately 

 much longer in young than old forms. 



Peristome moderate, calycinal area not large, but madreporite 

 very large and conspicuous. Primary tubercles more widely sepa- 

 rated above than below the ambitus, and the secondaries much 

 more numerous below than above it. 



In both ambulacral and interambulacral arete there is a con- 

 spicuous median space devoid of all but small tubercles and bearing 

 only small spines. About twenty-five plates in each interambu- 

 lacral row ; the primary tubercle which occupies its centre is very 

 conspicuous, has a wide spreading base, and stands well up ; there 

 are only a few secondary tubercles on these plates. The primary 

 tubercles on the interambulacral plates diminish more rapidly in 

 size towards the calycinal than the peristomial area ; at the ambitus 

 they are quite prominent. 



All the radial plates are shut out from the periproct ; there may 

 be one, two, or three largish tubercles on the inner border of each 

 interradial plate. 



Colour : the denuded test has a pinkish hue, of not so deep a red 

 as in E. microstoma, and not so patchy as in E. norvegievs. 



Diameter of 



In drawing up this diagnosis much use has been necessarily 



