566 BULLETIN OF THE UNITED STATES FISH COMMISSION. 
to the calcareous particles in the skin are purely arbitrary, but are quite generally 
used, and the figures given will prevent any misunderstanding. It must be borne in 
mind, however, that as holothurians increase in age the calcareous parts undergo 
considerable change, either becoming larger or smaller, more irregular or less so, 
and fewer or more abundant. The ambulacral appendages, especially the feet, are 
frequently much more numerous in adults than in young, and pigment is always more 
abundant with age. But the following key ought to enable anyone to distinguish 
even very young individuals of the species given. 
Key to the Holothurians of the Woods Hole region. 
Ambulacral appendages in the form of feet (pedicels) present, at least on the ambulacra. 
Pedicels chiefly or wholly confined to ambulacra; some scattered ones may be present on the back. 
Size large, up to 300 mm.; color some shade of brown Cucumaria frondosa. 
Size small, less than 00 mm.; color white or whitish Cucumaria pulciierrima. 
Pedicels scattered over the whole body, though the ventral ambulacrum may be distinctly defined. 
Size large, 75 to 225 mm.; body not noticeably attenuated posteriorly; color very dark Thyone briareus. 
Size small, less than 75 mm.; body much attenuated posteriorly; color brown Thyone scabra. 
Size small, less than 60 mm.; body not attenuated posteriorly; color white or whitish Thyone unisemita. 
Ambulacral appendages in the form of pedicels wanting. 
Tentacles 15: posterior end of body tail-like. 
Caudal appendage long; no reddish deposits in the skin Caudina arenata. 
Caudal appendage short, abrupt; reddish deposits in the skin Trochostoma ooi.iticum. 
Tentacles 12; no tail-like appendage. 
Color white or yellowish; radial pieces of calcareous ring pierced for passage of nerves Synapta ineoerens. 
Color red or pinkish; radial pieces of calcareous ring simply notched Synapta roseola 
1. Cucumaria frondosa (Gunnerus). Sea-cucumber. (PI. 11, figs. 65, 66; pi. 12, figs. 76-80.) 
Holothuria frondosa Gunnerus, 1770. 
Cladodactyla pcntactes Gould, 1811. 
Cucumaria frondosa Forbes, 1841. 
Botryodactyla grandis Ayres, 1851. 
Botryodactyla affinis Ayres, 1851. 
Pent acta frondosa Stimpson, 1853. 
Description. — Length in life, normally extended, 250 to 300 mm.; may extend to 600 mm. or more; 
diameter of body 90 to 100 mm., or much less when considerably extended. In life ventral surface 
much dorsal considerably, flattened, with sides curving upward; anterior end truncated; posterior 
end bluntly rounded. When disturbed, the body contracts to such an extent that it becomes ovoid 
or ellipsoidal, or almost spherical, and museum specimens usually show more or less of such con- 
traction. Tentacles 10 (sometimes 9 or 11), of approximately equal size and much branched; rather 
short and stout. Pedicels rather large, and forming a broad series on each ambulacrum, while 
slightly smaller and less perfect ones are scattered over the dorsal interambulacra; all lack the usual 
terminal, perforated calcareous plate. Calcareous deposits consist of irregular, usually smooth, per- 
forated plates (fig. 78), the size, number, and distribution of which vary greatly, though they are 
apparently most abundant in the young. The largest plates (fig. 80) are near the c.loacal opening, 
though they do not form so-called “anal teeth.” At the base of the pedicels and tentacles the 
plates become more irregular (fig. 79), and often bear minute projections, or more or less prominent 
ridges. Calcareous ring (fig. 76) very slender for so large an animal, and more or less imperfectly 
developed, perhaps according to age, being more perfect in smaller specimens; radial pieces some- 
what wider than interradial, with a very wide and deep notch in the posterior margin; the inter- 
radial pieces not notched posteriorly. Stone canal single, of moderate size, and provided with 1 to 6 
madrepore plates (fig. 77). Polian vessel usually single, very long, 100 mm. more or less. . Color in 
life deep reddish- or purplish-brown, darkest on the dorsal side and much lighter below, sometimes 
nearly white; pedicels often with a strong roseate tinge. 
flange. — -Greenland to Nantucket; also Iceland and Spitsbergen to Norway and the south coast of 
England; low water to 200 fathoms. The reported occurrence of this species on the Florida Reef is 
almost certainly a case of mistaken identification, and the records of its occurrence on the coast of 
Alaska and in the North Pacific are very probably based on Cucumaria japonica Semper, which seems 
to be quite a distinct species. 
