I'EDICELLATA. 399 



Others havo a furrow, more or less strongly marked, in the cliroction 

 of the obliterated band *. AVhen they are oval tliey constitute the 

 Brissus, K1.; 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- 

 thuriae. 



HOLOTHURIA, Lin. 



The Holothuriae have an oblong coriaceous body open at each end. 

 At the anterior extremity is the mouth, surrounded with com])licated 

 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 month 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 tw'o 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 mo\.ith 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 J. 



The Holothuriae may be divided according to the arrangement of 

 their feet. 



In some, they arc 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 Avhich are the head and anus, that are 

 narrower than the middle. The anus, in particular, terminates almost 

 in a point. Their tentacula, when developed, are very large. 



H. phantapus, L.; Mull, Zool. Dan., CXXII., CXXIII., 



Stockh. Mem., I767. 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. sputanyus, Seb., Ill, xiv, 3, 4, .5, 6, X, 22, ab. 19 ; Encyc, 158, 7 — U, 

 159, 1, 2, 3, &c. ; — Ech. radiatm, Kl., XXV ; Encyc, 156, 9, 10 ;—Spaf. suborbicu- 

 Jaris, Cuv., and Brong., Envir. de Par., 2d edition, v, 5 ; — Spaf. oniatus, lb.. 6. 



t Ech. purpurnts,M\ill., Zool. Dan., VI ;— Ef/i. 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. 



+ For the anatomy of the Holothurise see the excellent work of M. Tiedemann 

 already quoted. 



