A8TERIAS. 117 



2. OPHITTBA VTLOARIS. Plate XXVI 1 1 



Tins is the most common, and its varieties the most numerous, of 

 any that I have seen, insomuch, that it is somewhat perplexing to aay 

 what shall be assumed as the type of the species. 



The profusion and tin- distribution of colours in every different pro- 

 portion, distinguishes it among the rest, for yellow, blue, green, red, may 

 !> interspersed in a single specimen : Plate XXVTIl. fig. 1. Three linen 

 in length being a portion of the five rays of one specimen, were of uni- 

 form yellow from their origin, when the interspereion of other colours 

 commenced. 



Tin- finest specimens, which are found in the northern seas of Scot- 

 land, expand six inches between tlu- tips of the opposite m 



The proportion of the disc to the whole dfanaMUM of the animal i- 

 Miiall ; but the form and appearance not only undergo great modification 

 in attaining the adult state, but during the season of propagation these 

 are still more conspicuous. 



Early in the season ovoids begin to swell from the margin of the 

 disc between the rays. Advancing gradually through March and April, 

 they become so much enlarged in May and June, that the rays inter 

 posed between them seem reduced in size, and as if grown more slender. 



The ovoids, when mature, are full of a number of thin brownish or 

 yellowish foliaoeous lobes, composed of a vast multitude of ova. 



The rays of this species are particularly subject to mutilation. 



They are clothed by sets of hard and soft processes, adapted to va- 

 rious purposes. 



PLATE XXVI II 



Fio. 1. Opkiura mdgarii. 



2. Section of a ray, enlarged. 



3. Section of a ray. 



4. Cartilaginous organ of the ray. 



5. Spinous organ of the ray. 



6. Disc of a prolific specimen, surface. 



7. The same, under surface. 



8. Disc of a specimen, enlarged. 



9. Foliaceous lobe, from an ovoid, enlarged. 



