HCUINUS. 147 
completely bare. Below the ambitus the secondary tubercles are 
more numerous, and the miliaries are very well developed. The 
peristome is pentagonal and the gill-cuts slight. A bright red 
line extends along the twenty lines of the primary tubercles above 
the ambitus and give a very characteristic appearance to the test. 
A very considerable amount of variation is exhibited by :— 
(a) The form of the test. This is always much flatter in younger 
than older specimens, but the former vary in the extent to which 
they are respectively conical; the latter are sometimes more rounded 
than is typically the case, and the sharpness of the apical pole is 
sometimes a good deal blunted. 
(>) The length of the spines. The younger examples usually 
have the spines proportionately longer than the adult, but the latter 
vary very considerably among themselves. When the spines are 
short, they are sometimes more than ordinarily stout. 
(c) In many cases the bases of the spines are green, but they are 
sometimes red. 
Diameter of 
Diam. of r— “~ —————. Longest 
test. Height. Peristome. Calye. area. Periproct. spine. 
115 66 27 as ® 29 
115 60 27 20°5 9 36 
110 78 24-5 18°5 9 
50 30 18°5 12 a5 Re 
50 27 Ly ic a 28 
42 28 14 ‘c 4:5 26 
38 22 12 10 4-5 24 
30 12:5 10 ae ate 21 
23 11 9 21 
Distribution. Atlantic from Neiene and Halifax to Ascension ; 
North Sea; Mediterranean; off Kermadec Island. To 1350 fms. 
a. Off Tenby. Prof. W. N. Parker. 
a me S.W. Ireland. 
. S.W. Ireland, 55 fms. ‘Flying Fox’ Exp. 
n. 1 SW. Ireland, 110 fms. : Flying Fox’ Exp. 
o. S.W. Ireland, 150 fms. ‘ Flying Fox’ Exp. 
p. Galway Bay. Royal Dublin Soe. 
q. 20 miles off Achill Head, 20 fms. Royal Dublin Soe. 
s-u. Falmouth. W. P. Cocks, Esq. 
riba Weymouth. 
d'. Tynemouth. 
2. Echinus norvegicus. 
Echinus norvegicus, Dib, § Kor, Vet.-Akad. Hdlg. 1844 (1846), 
p- 268, pl. ix. figs. 33-39; Sars, Norg. Ech. (1861) p. 94; A. A 
Rev. Ech. (1872) pp. 125 & 296, pl. via. fig. 4; Wyv. Thoms. Pe, 
Trans. clxiv. (1874) p. 744; Mob. § Biitschli, ‘TB. Comm. Kiel, ii. 
& iii. (1875) p. 149; A. Ag. Chall. Rep. Ech. (1880) p. 117 ; td. 
Bull, Mus, C. wv; vill. (1880) p. 77. 
Kchinus (Psammechinus) norvegicus, Ag. § Desor, Ann. Sct. Nat. 
vi. (1846) p. 568. 
Psammechinus norwegicus, Daj. § Hup. Echin. (1862) p. 526. 
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