PEDICELLATA. 399 
Others have a furrow, more or less strongly marked, in the direction 
of the obliterated band *. When they are oval they constitute the 
Brissus, Kl.; but sometimes this furrow is deep and the shell is 
widened, assuming the figure of a heart f. 
Species of these two last forms are found in European seas. Their 
mouth is surrounded with ramous tentacula like that of the Holo- 
thuriz. 
Hotoruurra, Lin. 
The Holothuriz have an oblong ceriaceous body open at each end. 
At the anterior extremity is the mouth, surrounded with complicated 
tentacula susceptible of being entirely retracted. At the opposite 
end is the aperture of a cloaca, in which the rectum and organ of 
respiration terminate, the latter in the form of an extremely ramified 
hollow tree, which is filled with water, or emptied, at the will of the 
animal. The mouth is edentate, or merely furnished with a circle of 
bony pieces; it receives saliva from certain sac-like appendages. The 
intestine is very long, variously flexed, and attached to the sides of 
the body by a mesentery; there is a sort of partial circulation in an 
extremely complex and double system of vessels, entirely restricted 
to the intestinal canal, and in a portion of the meshes with which one 
of the two arborescent organs above mentioned is intertwined. 
There also appears to be a very attenuated nervous cord round the 
esophagus. The ovary is composed of a multitude of blind and partly 
ramous vessels, all terminating in the mouth by a small common 
oviduct; at the period of gestation they become enormously distended, 
and are filled with a red and grumous substance that appears to be 
the ova. Excessively extensible strings, inserted near the anus, 
appear to constitute the male organs of generation, and, consequently, 
these animals are hermaphrodites. When disturbed, it frequently 
happens that they contract so violently as to rupture and protrude 
their intestines t. 
The Holothuriz may be divided according to the arrangement of 
their feet. 
In some, they are all situated in the middle of the under part of 
the body, that forms a softer disk on which the animal crawls turn- 
ing up the two extremities, in which are the head and anus, that are 
narrower than the middle. The anus, in particular, terminates almost 
ina point. Their tentacula, when developed, are very large. 
H. phantapus, L.; Miill., Zool. Dan., CXXII., CXXIIL., 
Stockh. Mem., 1767. The envelope almost squamous; the feet 
of its ventral disk arranged in three series. From the seas of 
Europe. 
In others, the inferior surface is altogether flat, soft, and furnished 
* Ech. spatangus, Seb., I11, xiv, 3, 4, 5, 6, X, 22, ab. 19; Encye., 158, 7—11, 
159, 1, 2,3, &c. ;—Ech. radiatus, K)., XXV ; Encye., 156, 9, 10 ;—Spat. suborbicu- 
laris, Cuy., and Brong., Envir. de Par., 2d edition, v, 5 ;—Spat. ornatus, Ib.. 6. 
+ Ech. purpureus, Miill., Zool. Dan., VI ;—Ech. flavescens, Id., XCI, to which 
we should probably refer several of the shells united under Ech. lacunosus, such as 
Seb., III, x, 21; Encyc., 156, 7, 8. 
t For the anatomy of the Holothuria see the excellent work of M. Tiedemann 
already quoted. 
