SEA LILIES, STARFISHES, ETC. — CLARK. 65 



longer, straighter, stouter one ; close to this, but on the 

 furrow-margin is a large flattened spine, 2-2.5 mm. long and 

 about as wide as the length of the plate ; its outer side is more 

 or less deeply furrowed (at least near tip) and its summit is 

 a chisel-shaped or clavate edge ; approximately every other 

 spine is narrower, smoother and more nearly pointed, but 

 there is considerable diversity. On the actinal surface of a 

 very few plates, on the basal part of the ray, occurs a single, 

 low pointed tubercle or spine. Outside the series of adambu- 

 lacral plates occurs a very conspicuous series of spines, the 

 largest on the Starfish ; there are 2 of these to every 5 adambu- 

 lacral plates ; they are 2 mm. high or more, and their con- 

 spicuous chisel-shaped or clavate tips are frequently more 

 than 2 mm. wide ; outside this series, and virtually forming 

 the boundary of the actinal surface, is a series of similar but 

 smaller and more numerous spines, large ones often alternating 

 with small ones as in the adambulacral series. Papulae occur 

 between these two actinal series of spines. Oral plates and 

 spines not pecuHar or notable. Colour (dry), deep purplish- 

 brown, tips of the spines Hghter but apparently only by 

 abrasion. 



This is another remarkable Echinaster, unhke any previously 

 known, and making the fourth notable species known only 

 from Austraha, besides the long-knowTi East Indian species, 

 E. eridanella and African E. vestitus. It is interesting that 

 with one exception, each of these six species occurs on a 

 different part of the coast ; the present species E. superbus 

 comes from the far north-west of the continent ; two hundred 

 miles further south, at Port Hedland, E. vestitus and the very 

 different E. arcystatus have been taken ; over two thousand 

 miles of coast separate these three species from E. glomeratus 

 of South Austraha ; another gap of some one thousand five 

 hundred miles separates that sharply distinct species from 

 E. acanthodes of southern Queensland ; and just overlapping 

 the latter's area is the southern hmit of E. eridanella, the 

 common species of northern Queensland. Of course further 

 collections and studies may show that these geographical 

 lines of division do not really exist in nature but their apparent 

 occurrence seems worth noting. Unhke the various forms of 

 Echinaster in the West Indian region to which different names 

 have been given, these AustraUan species are very obviously- 

 different from each other and it is difficult to conceive of their 

 intergrading. 



Loc. — Broome, Western Austraha. 



