. Seaside studies in natural history. Marine animals. 100 MARINE ANIMALS OF MASSACHUSETTS BAY. 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 aU the tubes; between the five rows of ambulacral suckers are scattered irregu- larly certain appendages resembling suckers, but found on exam- ination not to be true locomotive suckers, and called on that Pig. account false ambulacra. These are the organs corresponding to the warts around the mouth of the Synapta. Although
. Seaside studies in natural history. Marine animals. 100 MARINE ANIMALS OF MASSACHUSETTS BAY. 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 aU the tubes; between the five rows of ambulacral suckers are scattered irregu- larly certain appendages resembling suckers, but found on exam- ination not to be true locomotive suckers, and called on that Pig. 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 £fll the tubes, yet the Pentacta does not use them indiscriminately as locomotive organs. In Pentacta, as well as in all Holothu- rians, 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. The correspondence between the different phases of growth in the , and the adult forms of the orders described above, the Synapta, Caudina, Cuvieria, and Pentacta itself, is a striking instance of the way in which embryonic forms illustrate the relative standing of adult animals. In the earlier stages of its development, the ambulacral tubes alone are developed in the Pentacta ; in this condition it recalls the lower orders of Holo- thurians, as the Synapta and Caudina ; then a sole is formed by the greater development of three of the ambulacra, and in this state it reminds us of the next in order, the Cuvieria, while it is Fig. 130. Pentacta frondoaa; expanded about one third the natural Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Agassiz, Elizabeth
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