HOLOTHURIA. 37 



end of June, whereby we shall attain more intimate acquaintance with 

 the true external structure of this singular being, which, concealing the 

 most interesting features of its organization, has hitherto appeared only 

 in disguise. 



In the natural sound and healthy condition, such a specimen as the 

 preceding adheres in the form of a crescent to any solid substance, the 

 body extending about three inches and a half. The anterior extremity 

 is quite obtuse, and the posterior tapers almost to a point, while both 

 are somewhat raised above the centre of the animal, whether it be 

 affixed to the side or the bottom of the vessel. When vigorous, the 

 Holothuria is always a crescent, and always in adhesion. 



This peculiar figure must be held a leading characteristic of many 

 species of Holothuriae, and has been evidently assigned to it by the Au- 

 thor of the animal world, for the faciUty of dischai^ging certain essential 

 functions. But the rarity of perfect specimens, and the difficulty of 

 preserving them in vigour, have undoubtedly precluded the notice of 

 naturalists to so definite a feature. Sometimes the curvature equals a 

 horse-shoe, therefore exceeding the proportions of a crescent. 



For the most part, absolute quiescence prevails through the day. 

 How strange it is, that this and so many other tenants of the deep, should 

 thus seem to slumber, — that we might almost affirm the sun had not been 

 created for a great multitude of the living world, as if light were unim- 

 portant to life ? But as he sinks beneath the horizon, the anterior of the 

 quiescent Holothuria swelling into still greater convexity, at length 

 opens to protrude a beautiful complex apparatus, as a substitute adapted 

 for the head and the hands of other creatures standing higher in the ani- 

 mal scale. Eight luxuriant, arborescent tentacular organs, each as long 

 as the wliole body, besides two antennulte of smaller dimensions, are un- 

 folded in the form of a funnel stretching beyond the shoulder. All 

 these organs radiate from the circumference of a short osseous and carti- 

 laginous cyUnder or case, with an orifice denoting the mouth in the 

 centre. The whole apparatus, released from concealment, is externally 

 expanded and withdrawn at will. — Plates IX., X. 



Soon, after display of this complex apparatus, the tentacula, ex- 



