Fig. 127. Cuvieria; natural size.
The Holothurian of our coast, excelling all the rest in beauty, is the Cuvieria. ([Fig. 127.]) As it lies on the sand, a solid red lump, with neither grace of form nor beauty of color, even the vividness of its tint growing dull and dead when it is removed from its native element, certainly no one could suspect that it possessed any hidden charm; but place it in a glass bowl with fresh sea-water; the dull red changes to deep vivid crimson, the tentacles creep out ([Fig. 127]) softly, and slowly, till the mouth is surrounded by a spreading wreath, comparable for richness of tint, and for delicate tracery, to the most beautiful sea-weeds. These tentacles, when fully expanded, are as long as the body itself. A limestone pavement composed of numerous pieces covers almost the whole surface of the animal; this apparatus corresponds, as we have already mentioned, to the warts containing anchors in the Synapta; but in the latter, the limestone particles are smaller, whereas in the Cuvieria they are developed to a remarkable extent. This animal is very sluggish, the ambulacral suckers, found only on three of the tubes, being arranged in such a way as to form a sort of sole on which they creep; the sole is tough and leathery in texture, but free from the limestone pavement described above. The young ([Figs. 128],[ 129]) are very common, swimming freely about, and more readily found than the adult; they are of a bright vermilion color, but the tentacles hardly branch at that age, nor is the limestone pavement formed, which gives such a peculiar aspect to the full-grown animal. The young Cuvieria, somewhat older than that represented in [Fig. 129], are found in plenty under stones at low-water mark, just after they have given up their nomadic habits, and when the limestone pavement begins to be developed.
Fig. 128. Young Cuvieria, much enlarged; l body, g tentacles. | Fig. 129. Somewhat older Cuvieria; l body, g tentacle round mouth, g' testaete of sole, b madreporic tentacle. |
Pentacta. (Pentacta frondosa Jäg.)
The highest of our Holothurians in structure, is the Pentacta. ([Fig. 130]) It is very rare on our beaches, though occasionally found under stones at low-water mark; farther north, in Maine, and at Grand Manan, it is very common, covering all the rocks near low-water mark. It is a chocolate brown in color, and measures, when fully expanded, some fifteen to eighteen inches in length. Unlike the Cuvieria, the ambulacral suckers are evenly distributed and almost equally developed on all the tubes; between the five rows of ambulacral suckers are scattered irregularly certain appendages resembling suckers, but found on examination not to be true locomotive suckers, and called on that account false ambulacra. These are the organs corresponding to the warts around the mouth of the Synapta. Although the ambulacral suckers are, as we have said, equally developed on all the tubes, yet the Pentacta does not use them indiscriminately as locomotive organs. In Pentacta, as well as in all Holothurians, whether provided with ambulacral suckers, or, like the Synapta and Caudina, deprived of them, the odd ambulacrum, viz. the one placed opposite the madreporic body, is always used to creep upon, and forms the under surface of the animal.
