3S0 



ECHINODERMS OF THE BRITISH ISLES 



disk usually irregular (Fig, 224, 6-7) (" Monaco ", Ixvi., p. 19, 

 Pis. I. 11-21, II. 1-2) .... M. rugosa Ker. 



5. A double series of long tube-feet in each ambulacrum, except 



the mid -ventral ; the whole body otherwise covered with 

 tube -feet, small on the ventral, larger on the dorsal side. 

 Deposits unknown (? absent) (" Talisman'' Holoth., p. 317) 



M. expectans Perr. 



A double series of larger tube-feet in the latero-ventral ambu- 

 lacra ; also in the anterior part of body the dorsal tube -feet 

 show a linear arrangement. Deposits with spire composed of 

 3 rods (" Monaco ", Ixvi., p. 15, PI. IV. 7-9) 



M. Murrayi, var. grandipes Her. 



Only a single series of larger tube -feet in lateral ambulacra 6 



6. Deposits exclusively of the 3-radiate type, with 3 component 



rods in the spire . . . . .3. M. lactea (Theel) 



Deposits partlj' of the 3-radiate, partly of the 4-radiate, type 7 



7. Rods of the spire ending each in a smooth point (Fig. 224, 8) ; 



disk with numerous holes (" Talisman " Holoth., p. 327) 



M. connectens Perr. 



Rods of the spire ending each in a long, serrate point (Fig. 224, 10). 



Disk usually with 7-8 peripheral holes {''Monaco'', Ixvi., 



p. 17, PI. I. 1-10) .... 



M. candelabra Her. 



Fig. 224. — Calcareous deposits (tables) of Mesothuria maroccana (1) ; 

 M. Murrayi (2-3, side view and from above) ; M. Verrilli (4-5, from 

 above and side view) ; M. rugosa (6-7, from below and side view) ; 

 M. connectens (8) ; M. candelabra (10) ; and Synallactes crucifera (9). 

 1, 4-5, 8-9. X 240. Magnification not stated on the originals of the 

 other figures. (After Perrier, " Talisman" Holoth. (1, 4-5, 8-9) ; Theel, 

 ''Challenger" Holoth., ii. (2-3); Herouard, ''Monaco", Ixvi. (6-7, 10).) 



