a 
478 THE VOYAGE OF H.MS. CHALLENGER. 
6. Bathymetrical range: 6 to 640 fathoms. 
Greatest range of one species: Retaster multipes, 124 to 640 fathoms. 
All the other species whose depth is known are confined to the Littoral zone, 
with the exception of Retaster gibber, which extends into the Continental zone. 
y. Nature of the Sea-bottom: Retaster multipes occurs on greenish clay; Retaster 
verrucosus on Sand ; Retaster peregrinator on Voleanic mud ; Retaster gibber 
on Blue mud; fetaster insignis on Coral mud and Green mud. 
‘The species collected by the Challenger are indicated in the above list by an asterisk. 
Chorological Synopsis of the Species. 
Ocean. Range in Fathoms. Nature of the Sea-bottom. 
Retaster capensis . : . | Atlantic. | 
| { Indian and Eastern | 
taster cribrosus = Ils : 
Retaster cribrosus |) Archipelago. 
Retaster gibber . : é Pacific. | 245 Blue mud. 
Retaster insignis . é : aS eg To \ | 6 to 25 Coral mud ; Green mud. 
and Pacific. J : 
Retaster multipes . ; . | Atlantic. 124 to 640 Greenish clay. 
Retaster peregrinator . . | Southern. 127 Volcanic mud. 
Retaster verrucosus ; 4 | Atlantic. 55 Sand. 
1. Retaster verrucosus, Sladen (Pl. LXXVLI. figs. 1 and 2; Pl. LXXVII. figs. 9 and 10). 
Retaster verrucosus, Sladen, 1882, Journ. Linn. Soc. Lond. (Zool.), vol. xvi. p. 196. 
Marginal contour moderately indented in the interradia, which are angular and not 
rounded ; outline of the rays gracefully curved outwards. The minor radius is in the 
proportion of 59°5 per cent. R=47 mm.; r=28 mm. Abactinal profile moderately 
high and rounded, tapering gradually to the extremity of the rays, which are slightly 
upturned and expose the ambulacral furrow on the abactinal area. Actinal surface flat. 
The supradorsal membrane is very regularly and uniformly reticulated. The paxille 
have long pedicles, and bear a crown of about fifteen spinelets, nearly as long as the 
pedicle. The central spinelet, which is very much more robust and longer than any of the 
rest, stands perpendicular, rising in the centre of the mesh, whilst the others, which are 
slender and delicate, radiate round it and outward to the fibrous bands that form the 
outline of the mesh, The median spinelet is much more prominent than any of the others ; 
and the thick fleshy cap formed upon it by the supradorsal membrane imparts a very 
conspicuous papillate appearance to the starfish, assuming in large specimens almost a 
semi-tuberculate character of great regularity and evenness of disposition. In fully grown 
specimens the whole membrane becomes very thick and wrinkled, rendering it difficult to 
trace the radiating bands; in moderate-sized specimens, however, they may be clearly 
distinguished without removing the epidermis. From the central spinelet six to eight 
