ECHINI IS. 



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. 



(h) 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 



Distribution. Atlantic from Xorway and Halifax to Ascension ; 

 Xorth Sea ; Mediterranean ; off Kermadec Island. To 1350 fms. 



a. Off Tenbv. Prof. W. X. Parker. 



b-d. SAY. Ireland. 

 e-m. S.W. Ireland, 55 fms. 



n. S.W. Ireland, 110 fms. 



o. S.W. Ireland, 150 fms. 



p. Galwav Bay. 



q. 20 miles off Achill Head, 20 fms. 

 8-w. Falmouth. 



a'-^ 1 . | Weymouth. 



d ' . Tynemouth. 



' Flying Fox ' Fxp. 

 ' Flying Fox ' Fxp. 

 ' Flying Fox ' Exp. 

 Royal Dublin Soc. 

 Royal Dublin Soc. 

 W- P. Cocks, Esq. 



2. Echinus norvegicus. 



Echinus norvegicus, Bub. §• Kor. Vet.-Akad. Hdlg. 1844 (1846), 



p. 268, pi. ix. figs. 33-89 ; Sars, Norg. Ech. (1861) p. 94 ; A. Ag. 



Rev. Ech. (1872) pp. 125 & 296. pi. vi a. fig. 4 ; Wyv. Thorns. Phil. 



Trans, clxiv. (1874) p. 744 ; Mob. fy Biitschli, JB. Convn. Kiel, ii. 



& iii. (1875) p. 149; A. Ag. ChaU. Rep. Ech. (1880) p. 117 ; id. 



Bull. Mus. C. Z. viii. (1880) p. 77. 

 Echinus (Psammechinus) norvegicus, Ag. Sf Desor, Ann. Sci. Nat. 



vi. (1846) p. 368. 

 Psammechinus norwegicus, Duj. § Hup. Echin. ( 1862) p. 52C. 



l2 



