OCEAN LIFE. 25 



while on the other they as obviously approximate the annulose 

 animals, to which the most perfectly organized amongst them 

 bear a striking resemblance. In Ophiurus, the rays are long 

 and simple, resembling the tails of so many serpents a circum- 

 stance from whence the name of the family is derived. Never- 

 theless, on each side of every ray we still trace movable lat- 

 eral spines, which, although but mere rudiments of what may 

 be seen in Comatula, may still assist in locomotion, or perhaps 

 may contribute to retain the prey more firmly when seized by 

 the arms. The rays themselves are composed of many pieces 

 curiously imbricated and joined together by ligaments, so that 

 they are, from their length and tenuity, extremely flexible in all 

 directions, and serve not only for legs adapted to crawl upon the 

 ground, but are occasionally serviceable as fins, able to support 

 the animal in the water for a short distance by a kind of undu- 

 latory movement. The body, or central disc, is beautifully con- 

 structed, being made up of innumerable pieces accurately fitted 

 together. The mouth occupies the centre of the ventral surface, 

 and is surrounded by radiating furrows, in which are seen minute 

 apertures that give passage to a set of remarkable prehensile 

 organs; these are calculated to act as suckers, and so disposed 

 as either to fix the body of the animal, or to retain food during 

 the process of deglutition. In Ophiurus we have just mentioned 

 the existence of protrusible suckers around the opening of the 

 mouth, well adapted, from their position, to take firm hold of 

 food seized by the animal ; and it is by increasing the number of 

 such organs that ample compensation is made for the loss of mo- 

 tion in the rays themselves in the star-fishes. On examining the 

 lower surface of an Asterias, even in those forms which most ap- 

 proximate a right-lined pentagon in their marginal contour, the 

 number of rays will still be found to be distinctly indicated by as 

 many furrows radiating from the mouth, and indicating the centre 

 of each division of the body. These ambulacral furrows, as they 

 are termed, exhibit, when examined in a dried specimen, innu- 

 merable orifices arranged in parallel rows, through each of which, 

 when alive, the animal could protrude a prehensile sucker, capa- 

 ble of being securely attached to any smooth surface. No verbal 

 description can at all do justice to this wonderful mechanism, 

 4 



