Ill 



nOLOTHCRIADA 



IIOLOTHURIAD^E. 



ill 



to the kidneys ia birds, tartly Ac. There we small oblong 

 ' t opening of UM principal trunk into the rectum. 8, A 

 of hollow round tube*, all entering into one duct, 

 the bead. The- will be beM ssen in another plate 



to be 



i open* at the head. Theee will be best seen in another plate 

 i will be published ia the fasciculus of the catalogue relating to 

 atioo. , V easels which seem to have neither beginning nor end, 

 m vena portorum : " they appear," adds Mr. Hunter, 

 I 1 *"**"*; at on* end while they are ramifying at the other ; 

 i* the ~Jli*W end, and which the ramifying, I do not 

 . however H is possible on* end is the absorbing system, the 

 other Ih* arterial Whenever there i* a heart one commonly can 

 make out UM motion of UM blood from and to that viscus ; but 

 whsr* w* ars deprived of that puide it becomes difficult to determine." 

 10, A distinct VMS*! from the former. These parte are indicated in 

 theptato. 



The preparation No. 984 (Physiological Series Gallery) in the 

 i of UM Royal College of Surgeons, is the specimen of //o/o- 

 " lid open, and the alimentary canal and generative 

 to show the respiratory organs, which have been 

 injected. These organ* consist of two elongated, hollow, ramified 

 piuussses, commencing by a common orifice from the closed cavity, 

 and extending towards the opposite end of the body. One of them is 

 ia more immediate connection with the alimentary canal, and is 

 abundaotlv supplied by ramifications of the intestinal vessel, the con- 

 teat* of which are thus brought into necessary communication with 

 th* sea water introduced into the tubular bronchia from the cloaca. 

 The other gill is more closely attached to the parietes of the body, 

 and probably *erv*s to aerate the vessel* of thst part. ('Cat.,' voL ii.) 

 To this Professor Owen adds, that in the description of the Jfolotkuria 

 above quoted, Mr. Hunter attribute* to the*e organs a more limited 

 bar* in the great excretory functions than they undoubtedly perform, 

 regarding them, from their connection with the cloaca, as analogous 

 to UM kidneys of the higher animal*. Distinct urinary organs are 

 not however, observes the Professor, developed until we arrive at a 

 much higher point in the scale of organisation than the J/olothuria 

 and iu mugenoi* attain to ; the preparation is therefore placed in the 



!>-Fi*hes,' Professor E. Forbe* makes the follow- 

 ing general observations on this family : 



" A Siltlkmrim may be regarded in one light as a soft Sea-Urchin, 

 in another as a radiated animal, approximating the Annelides. The 

 radiation of the surface is more or less complete in all the genera of 

 Holoikvnmda : the internal organisation is mostly bilateral The akin 

 i* usually soft and leathery ; in a few genera strengthened by calcare- 

 ous or horny spines. Five avenues of suckers separate the body into 

 as many longitudinal segments, which in the majority are of equal or 

 Dearly equal dimensions. In some the suckers are developed only on one 

 id*, so that th* animal when creeping present" in a manner a back and 

 a b*Uy. The sucker* are similar to those of the true star-fishes and 

 M-urchins. Besides progression by means of these suckers, the 

 ilettsyiWa move as Annelides, by the extension and contraction of 

 'ndiea. They have a mouth and an anus, each terminal, and 

 at opposite extremities of their bodies. The mouth is siir- 

 I by plumose tentacula, the number of which, when they are 

 e, U always a multiple of five ; but as these animals are 

 ingnkriy subject to the loss or absence of parts in individuals of the 

 various specMS, much confusion has arisen from the establishment of 

 supposititious species from characters founded on abnormal numbers 

 of th* parts. 



" The tentacula an ramose cirrhi ; they can be retracted within the 

 mouth, and sometimes when in captivity the animal will not exsert 

 them for days together, though otherwise active. They are drawn in 

 with UM akin, and when we cut open a ffolotkuria having its tentacula 

 retracted, w* find them in the centre of a dental circle. The circle of 

 teeth i* snaloguus to that of the Erhini The oesophagus pane* 

 through it, and open* into a more or less muscular stomach, from 

 which an intestine, often rsrr complicated, proceeds to the posterior 

 rtrwnity of the body, where it opens into a funneliibaped cloacum, 

 nto which also open UM two tree-like respiratory organs. There is a 

 viMulir circle (and some say a nervous cord) surrounding the mouth, 

 an I vessels are distributed from it to various parts of the body and 

 One or more sacs of a pyriform shape depend from a vessel 

 1 [ UM pharynx, and are by many believed to be salivary 

 r. Oo.-l.ir has found a sac containing calcareous concre- 

 i on oo* side of the mouth in certain species. This he regards a* 

 madraporifarm tubercle or nucleus, the ovaries are in many 

 DM*** v*ry numerous in others very few, and unite to form a tube 

 which opsos at oo* aid* toward* the upper extremity of the animal 

 TU inner surfaon of th* anitnal'. skin u lined with powerful longi- 

 textiaal and tnoven* muscles, by means of which the creature con- 

 Mi body and lengthens it out in many directions, changing it* 

 Sometimes the creature eject* all iu 



It is 



fan* to a wonderful 



TfcMsn, or burst* UM body with iu convulsive contraction*. .. 

 JSMlr/ stated that the AtMtarte do so whenever they are taken, 

 but *Mh i* not UM ow*. I have never seen the animal disgorge its 

 tsrtiiss, but siisriniins of many species have I seen in which there 

 w* not a trace left of UM creature's bowrls and other internal organs, 

 though H MOMd, when taken, alive and healthy. It is astonishing 



how long they can live deprived of the most essential parte of their 

 organism. Sometimes they are found wanting the respiratory organs, 

 and sometimes the generative tubes are deficient, and these deficiencies 

 so frequently occur that we should, be extremely shy of proclaiming 

 differences in the internal structure of species; and when we see 

 genera and species (as has been the care) anatomically defined from the 

 want of respiratory trees or genital tubes, we should be extremely 

 cautious about admitting such, and rather regard such want* as 

 accidental deficiencies in a few specimens than as organic peculiarities. 



" The Jfuloihunadrr are generally distributed through the seas of 

 the globe, but are congregated in greatest numbers in the Eastern 

 sea*. On our shores they are rare and unattractive animals, not often 

 seen even by the zoologist; but abroad they are very abundant and 

 in some places used as food. Of one genus, the Trepang, many species 

 are eaten. In Mr. F. D. Bennett's interesting ' Account of a Whaling 

 Voyage round the World,' we are told that there are two kinds of 

 Trepang abundant on the rocks at Raialia, and that they are very 

 indolent animals. ' When handled,' says Mr. Bennett, ' the Trepang 

 contracts its body in a longitudinal direction, and should its tentacles 

 be expanded they are instantly concealed ; but no noise or agitation 

 of the surrounding water will excite these symptoms of alarm, or 

 cause any attempt to escape. They usually lie exposed in the shallow 

 waters, though we have very often seen them buried in beds of coral - 

 sand, their plumy tentacles being alone exposed, and floating in the 

 water above, apparently as a lure for prey. Some may also be 

 observed lying on the rocks, their bodies completely encrusted with 

 coral-sand, which may either have been accumulated by a previous 

 burrowing, or thus used as a disguise. It would appear to be partly 

 the instinct of the animal to take its prey in ambush, but what that 

 prey is, as well as the entire economy of these moluscs, remains a 

 perplexing mystery. Their intestines invariably contain many hard 

 and solid masses of madreporic rock or tree-coral, some of them iiiim- 

 than an inch in length, and all moulded as pellets to the calibre of 

 the intestinal canal. 



" It ia difficult to say bow these stony bodies have been obtained by 

 the Trepang, though it is easy to conceive that they may be rendered 

 serviceable as nutriment, by the anaimilntion of the animal matter 

 they contain. It u this animal which the Malays of the Oriental 

 Isle* seek so diligently for the supply of the China market, where it 

 obtains a good price if well preserved. 



*' It is employed by the Chinese in the preparation of nutritious 

 soup, in common with an esculent sea-weed, sharks' fins, edible bir.U'- 

 nestc and other materials, affording much jelly." Jseger say tlio 

 intestines are extracted, the animal then boiled in sea-water and drud 

 in smoke. 



The British Holothuriadtt belong to four families, namely : 



1st. The Ptolidtr, or Ascidian Hotothnriad<r, animals approaching 

 {he Mollutca in their form, and having a soft circumscribed di- 

 the foot of a Gasteropodoua Mollusc, on which the suckers are placed 

 for progression. [Psouo.E.] 



2nd. The PentacUt, which bare the suckers arranged in five regular 

 rows, and are more or less angular in form. [PBNTACT.K] 



3rd. The Thyontt, which have the suckers scattered all over the 

 surface of the body. [THTOXEB.] 



4th. The Synapla, in which there are no suckers on the body, the oral 

 tentacula being the only representatives of those organs. (SVN 



I >e lilainville refers the difficulty of the distinction of the species 

 of Uoiothuriada to the following, among other causes : 



1. The general form is extremely variable. When the animal is in 

 a state of tranquillity in the enjoyment of all its faculties at the 

 bottom of the water, it is, iu the greatest number of canes at least, 

 very much elongated, often cylindrical, and almost vermiform : on the 

 contrary, when in a state of repose, it becomes much xhurti-r ami 

 ordinarily more convex in the middle than at the extremities. \Vii.-n 

 it is irritated, whether iu or out of the water, tho contractile action 

 becomes stronger, and the animal can no longer be recognised, r.nt. 

 it is especially when it has been plunged iu, spirit, that the form <lil!.n 

 totally from that which the living animal exhibits. 



2. The size, the form, and distribution of the more or less niam- 

 millated tubercles which are numerously spread over the skin, :. i 



to M. I)e lilainville to offer too great a number of variations to permit, 

 of their being employed in distinguishing specific character. 



3. The tentaculifomi suckers, which have their exit through the 

 pores or holes in the skin, and by means of which these nninmli 

 attach themselves to submarine bodies, are, in a certain nun. 

 species, spread nearly equally over the whole su)>erficies of tho body ; 

 but in others they are accumulated on the lower surface, without 

 order, in a determinate order, or are disposed in double series upon 

 five longitudinal lines, as in H. pentacla. 



4. The more or less terminal position of the two orifices may, M. 

 I)e lilainville thinks, be taken into consideration advantageously. 



6. Home zoologists, and among others M. Lesueur, says M. De 

 Blainville, attach a great importance to the number of the tentacular 

 appendages of the mouth, and to their form and mode of division ; 

 but, M. De lilainville fears, erroneously, for he bos been positively 

 assured that the most common species of the Mexiiterrancnn, // 

 futniom, which is found in hundreds at Toulon, varies much, both a 

 to the number and terminal divisions of these organs. 



