THE PENTACTE. 543 



bery tentacles, that are at the least disturbance entirely withdrawn, and concealed internally. 

 This is one of the most desirable objects for the aquarium. On the under surface is a flat, 

 disc, provided with small tubes, which answer as propelling organs. These tubes have disc- 

 shaped terminal parts, which adhere to surfaces it passes along. The same are seen in appro- 

 priate portions of the Sea Urchins. A few small species are found at Grand Menan, but the 

 home of these forms is in tropical waters. The Pentacta is represented in our New England 

 waters, and other forms, similar to the Cucumarias. The most notable of these forms is seen 

 on the Florida Reef. A species of Holothuria inhabits the lagoons at Tortugas, measuring 

 two feet in length. It is much like a great cucumber in appearance, though it is black and 

 uninviting in aspect. These creatures are strewn along the bare places among the shrub corals 

 of the lagoons in considerable numbers. Remove one of them and submerge it in a pail of 

 water, the huge creature exhausts the oxygen very quickly. Another creature now protests 

 there is not enough of the life-giving agent, and appears from the mouth of the great Holo- 

 thurian, in the shape of a veritable fish, six or eight inches in length. Delicate, almost white, 

 from its absence from light, it seems to have little faculty for swimming, though it is 

 possessed of every ordinary requisite of fins. Careful as possible with this fish, we never 

 could keep it alive an hour. Here is a singular case of commensalism. Chaucer is credited 

 with the invention of the word commensal, as literally meaning eating at the same table. 

 Naturalists have adopted this term to distinguish the cases like the present, where two 

 creatures are intimately associated. 



The Holothurias are prepared for food, and a large species, the Trepang of the Chinese, 

 inhabiting the Pacific Ocean coral reefs, is similar to the great one just described. They are 

 gathered on the reefs and "cured" there, when they are exported to Chinese ports in great 

 quantities. Our friend Stimpson, of fame in these regions of the invertebrates, "cured" our 

 smaller Holothuria, of Grand Menan, and pronounced it equal, at least, to the article of the 

 Chinese markets, with which he was familiar. Our friend .had personal experience in various 

 other directions, to wit, in one case, testing the "smarting" powers of the tentacles of one of 

 the great jelly fishes. Not content with the ordinary method of touching, he applied his 

 tongue with positive results as to potency. 



A form of Holothurian is quite often thrown up on the beaches of New England after 

 storms, which is very attractive from its pearly-white, soft, leathery exterior, and a beautiful 

 pinkish blush on one side. This was called CMrodota by Gould, and is altered to the Synaptas. 



An odd-looking little creature among them, called the PSOLINUS, is remarkable for the 

 great length of the ambulacra?, which lift it well above the object on which it walks. Owing 

 to this fact, it has quite an intelligent aspect as it crawls along, with its beautiful crown of 

 tentacles expanded, and waving in the water. In these two curious genera, the ambulacrse 

 are only distributed in the under surface, and in the present example are placed in three rows 

 on a flattened disc, which occupies part of the under surface. 



In the genus PENTACTE, the ambulacrse are placed in a series of parallel rows along the 

 body, sometimes six, but mostly five in number. 



It is a remarkable fact, that when one of the Holothuridse is alarmed, or suffers from 

 indigestion, or is affected in any way, it proceeds to an act which is the exact analogue of the 

 Japanese custom of "happy despatch." Under any or either of these circumstances, it 

 proceeds to disembowel itself, and does so with a completeness and promptitude that are 

 almost incredible. It disgorges the whole of its interior, with all the complicated arrange- 

 ments that render the Holothurida3 such singular beings to dissect, casts away all its viscera, 

 its stomach, and even throws off the beautiful bell of tentacles. 



Having done this, and reduced itself to the condition of an empty skin, which cannot eat 

 because it has no mouth and no stomach, and will not walk, because it has no object for 

 locomotion, it remains perfectly quiescent for some months. At the expiration of that period, 

 a fresh set of tentacles begin to make their appearance ; they are followed by other portions ; 

 and after a while, the animal is furnished with a completely new set of the important organs 

 which it had cast away. It seems a singular cure for indigestion, but no one can deny its 

 efficacy. 



