128 



LIFE BY THE SEASHOKE. 



distinctly reticulate or netted skeleton, with minute spines 

 on the meshes of the net. Between the meshes there are 

 in some places pores through which little sacs, or skin-gills, 

 can be protruded. The rays taper very gradually, and have 

 a very narrow ventral groove with two rows of tube-feet. 

 At the sides of the groove there are dense rows of small 

 spines. The species is interesting because it extends over a 

 very wide area, not only horizontally but also vertically; for 

 it lives from the shore down to great depths. About two to 

 four inches from ray to ray may be given as a common size 

 for shore specimens, though the animal does grow to a much 

 larger size. It is very variable, varying greatly not only as 

 to colour, but also as to the degree of development of the 

 spines, and even the number of rays. It is not uncommon 

 to find four- or six-rayed specimens, though normally the 

 number is five. 



Our list of littoral starfishes is so short that when we 

 have named the sun-star (Solaster papposus, see Fig. 41), 



we have named all 

 that are likely to 

 occur in the living 

 state between tide- 

 marks on the East 

 Coast. Our common 

 sun-star reaches a 

 large size, and may 

 be recognised by the 

 fact that it has twelve 

 or more rays. Like 

 so many starfishes, 

 it varies greatly in 

 colour usually pur- 

 plish red blotched 

 with white, it is 

 sometimes pure red, 

 and sometimes 

 orange. The dorsal 

 surface is covered with peculiar spines of large size, which 

 are separated by spaces through which the little skin-gills 

 emerge in life. Each of these dorsal spines consists of a 

 pillar, bearing at its top a cluster of crowded spines, pro- 



Fio. 41. Solaster papposus, or sun-star. Note the 

 round madreporite to the left of the central disc. 



