SEA-STARS AND SE.-URCHINS. 97 



Another spocies, the Long-armed Brittle-star (Ophiocoina 

 brachiatd), has the rays about twenty times the diameter of the 

 disk, each consisting of three or four hundred joints; so that 

 if one reckons up the four plates that go to make one joint, 

 then adds to these the eight to ten spines on each joint, and 

 multiplies the first total by say three hundred and fifty (the 

 number of joints), and this second total by five (the number of 

 rays), one gets a grand total of seventy thousand pieces, con- 

 stituting merely the external covering of the rays of this small 

 creature leaving entirely out of the reckoning the internal 

 bony framework upon which these are placed. 



These Brittle-stars go through a peculiar stage of existence, 

 prior to their assumption of rays. When summer is verging 

 upon autumn, their minute larval forms may be gathered in a 

 fine muslin net, from the surface of the sea. Gosse has given 

 a description of this stage with admirable brevity. He says : 



11 A painter's long easel affords the only object with which 

 to compare the little creature ; for it consists of four long, 

 slender, calcareous rods, arranged two in front and two 

 behind, with connecting pieces going across in a peculiar 

 manner, and meeting at the top in a slender head. On this 

 shelly, fragile, and most delicate framework, as on a skeleton, 

 are placed the soft parts of the animal, a clear gelatinous flesh, 

 forming a sort of semi-oval tunic around it, from the summit 

 to the middle ; but thence downward the rods, individually, are 

 merely encased in the flesh, without mutual connection. The 

 interior of the body displays a large cavity, into which a sort 

 of mouth ever and anon admits a gulp of water. Delicate 

 cilia cover the whole integument, and are particularly large 

 and strong on the flesh of the projecting rods. 



"The appearance of this most singular animal is very 

 beautiful ; its colour pellucid-white, except the summit of the 

 apical knob, and the extremities of the greater rods, which are 

 of a lovely rose-colour. It swims in an upright position, with 

 a calm and deliberate progression. The specimens which I 



