44 ON THE COMMON BRITTLE STAR. 
gradual secretion of joints, plates, and spines; to the two former 
I need not here allude. 
From each side of the first-mentioned lobes are produced little 
warts or protuberances which give origin to four flat fan-shaped 
radiating spines, standing out on each side (see Fig. 1). Thenext 
segment is at first much the same, as far as the plates and fleshy 
portions are concerned, but not so the spines, for in this case the 
lateral shoots produce two claws, at first nearly straight, but as 
they increase in size, they gradually assume a clawed form, much 
bent inwards, and having, in addition to the curve at the apex, 
one, and sometimes two, hooks between the tip and base. 
While these claws are being formed, the lobes from whence 
they are produced are pushing out between them in a straight line 
a fleshy prolongation, which secretes a long plate on its upper 
surface, and various others imbedded in its substance,* and at the 
same time sends out two small warts at the base of the claws, 
which in this early stage of the life of the Star-fish, each pro- 
duce two broad radiating spines to a certain extent like those first 
formed. 
This latter order of development is repeated again—once, or 
even twice, the only difference being, that in the subsequent 
productions the flat radiating spines gradually give place to others 
of a more pointed character. 
The “Star” being now possessed of three or four joints to each 
ray, puts out another, and with it its customary lobes; these as 
usual secrete the claws and spines, but now and henceforth the 
spines are in each case long, jagged, and pointed—no more of a 
flat radiating character being seen; and this goes on, joint after 
joint being added, the lobes secreting perforated plates, at first 
slightly oval, irregular and removed from each other, but as they 
increase in size, they gradually approach and assume the shape 
seen in mature specimens. 
Tf we take a moderately large Brittle Star and carefully ex- 
amine it near the disc, it will be seen that the spines are long and 
pointed, and set in rows upon the rays from the upper to the 
* These plates are at first more like a coarse net, but as they increase in size, the inter- 
spaces are much filled up, and produce a closer texture. 
