VERMES. 



The following zoophyte? yield nearly the fame refults ; 

 viz. madrepora fafcicularis ; millepora ceDulofa, fafcialis, 

 and truncata ; and ifis hippuris. 



Merat-Guillot gives the following flatement of the com- 

 pofition of three fpecies, which muft, according to this 

 account, be referred to the prefent clafs. 



-(Vhhe Coral. Red Coral. 



Carbonate of lime 

 Animal matter 



50 

 5° 



53-5 

 46.5 



An".ft:iated 

 Coralline. 



49 



5' 



100 



3. Immerfion in weak nitric acid does not afFeft the (hape 

 of the madrepora polymorpha : there remains a tough, 

 opaque, membranaceous fubftance of a white coloui;, filled 

 ivith a tranfpaitent jelly. The acid folution yields a flight 

 j)recipitate of phofphate of lime, when heated with ammonia, 

 and carbonate of ammonia throws down a copious precipitate 

 of carbonate of lime. It confifts, therefore, of animal matter, 

 partly ill the ftate of jelly, partly in that of membrane, hard- 

 ened bv carbonate, together with a little ph.jfphafe of lime. 



The fluftra foliacea, corallina opuntia, and ifis ochracea, 

 gave the fame refults ; except that in the two latter, phof- 

 phate of lime could only be difcovered in the folution of the 

 burnt fubftance. 



The colouring matter of the ifis ochracea falls down in a 

 fuie red powder in weak nitric or muriatic acid ; whereas 

 that of the tubiiiora mufica, and of the gorgonia nobilis, or 

 red coial, is dellroyed by thcfe acids. 



After the red coral has been immerfed in acid, it is feen 

 to confift of two parts, vh. an extf-rnal tubulated mem- 

 lirane of a yellow colour, inclofing a tranfparent gelatinous 

 fubftance. The acid folution yields only carbonate of 

 lime ; but when the red coral is heated to rednefs, and 

 then diflblved, the folution. yields a little phofphate of 

 lime alio. Red coral then confifts of an internal ftc-m, 

 compofed .of gelatinous matter and carbonate of lime ; 

 and an external covering or cortex, confifting of membrane 

 hardened by the calcareous falls ; and both coloured by 

 fome unknown fubftance. 



The gorgonia ceratophyta and fiabellum have a fimilar 

 compofition. The cortex of the gorgonia fuberofa contained 

 a httle phofphate and a large portion of carbonate of hme. 

 The llem contained icarcely any earthy fait. The gorgonia. 

 fetofa and peftinata exhibited nearly the fame phenomena. 



4. Gorgonia antipathes has a horny ftem, but is deftitute 

 of cortex. It gives out fome gelatine to boiling water. 

 When fteeped in nitric acid, it becomes foft, and exhibits 

 concentric coats of thin, opaque, brown membranes, of a 

 ligneous afpeft. With potafh it forms an animal foap, and 

 pofleffes nearly the properties of horn. The ftems of the 

 gorgonia umbraculum and verrucofa are fimilar ; but they 

 both poflefs a cortex, competed of membrane and carbonate 

 of lime. 



Mr. Hatchett analyfed many fpecies of fponges : but 

 found them all iimilar in their compofition. They confift of 

 gelatine, which they gradually give out to water, and a thin 

 brittle membranous fubftance, which polfeffes the properties 

 of coagulable albumen. 



■ The alcyoniums refeinble verv much in their compofition 

 that of the gorgonia fuberofa. They yield a little gelatine 

 to water. They are foftened, and appear membranous in 

 nitric acid, which takes up the carbonate of hme, and likewife 

 a little phofphate, at leaft when the fubftance has been pre- 

 vioufly heated to rednefs. 



In the Annales du Mufeum d'Hiftoire Naturelle, we 



have an account, by A. Laugier, of the earthy and faline 

 matters contained in the hquor produced by the fpontaneous 

 decompofition of the medufae. This was procured by the 

 melting of a blue medufa taken in the Channel. When left 

 to fpontaneous evaporation, a cryftalline peUicle formed, and 

 was removed, and fo on fucceffively, until no more cryftals 

 were formed. " The fait thus obtained," fays the author, 

 " was formed of carbonate and phofphate of lime ; thefe 

 falls exifting in exaftly the fame proportions as in all the 

 calcareous concretions, produced by the hardening juices of 

 the mollufca, the polypes, and the cruftacea, which I have 

 examined, fuch as red coral, white coralline, oyfter-fheUs, 

 crab's-eyes, &c. viz. carbonate of lime 92, phofphate of 

 lime 7, animal matter uniting the molecules i, in 100 

 parts. See p. 346. 



The remaining liquor, being evaporated to drynefs, gave 

 a fahne refidue, of which the component parts, fimilar to the 

 falls of the fea, were, in 100, muriate of foda 79, muriate 

 of lime 4, muriate of magnefia 3, muriate of iron 2, ful- 

 phate of lime l, water and lofs 11. P. 349. 



So complete, fays Peron, is the fpontaneous fufion of the 

 medufa?, that from an individual weighing feveral kilo- 

 grammes, hardly a few milligrammes of membranous refidue 

 remain in the filter. Ann. dn Muf. t. xv. p. 43. 



Organs of Motion. — In the cephalopodous mollufca. 



The mollufca, which have the iiead furnilhed with long ap- 

 pendages for progrefllve motion, are called cephalopoda ; 

 and have two orders of mufcles, one belonging to the body, 

 the other to the feet or tentacula. 



The fac which compofes the body of thefe animals, 

 ftripped of the external fl<in, prefents a mufcular tifiue of 

 very compaft fibres. Thofe of the outer layer appear to 

 have a longitudinal direftion ; the middle layer is tranfverfe ; 

 and the iucceeding layers have different obliquities. They 

 can flatten, elongate, twift, and bend the lac ; bift the 

 aclion of each layer cannot be afligned in a pofilive manner, 

 on account of their very complicated ftruClure. 



In the back of thefe animals, under the Ikin, there is 

 found a body more or lefs folid. In the cuttle-fifti it is a 

 fpecies of bone compofed of different thin paraUel plates 

 one above another, and feparated by httle columns difpofed 

 in the form of quincunces. This bone is oval, thick to- 

 wards the middle, and thin at the circumference. In other 

 fpecies, its form varies much, but its fubftance is generally 

 elaftic, and tranfparent like glafs. Its furface is fometimes 

 marked with longitudinal furrows. 



The fepia oftopus war.ts it entirely. 



Two Ifrong mufcles arife from the inner furface of the 

 fac, on each fide of this bone. They run towards the head, 

 and on their arrival there, divide each into two branches; 

 one branch is inferted into the head, the other mixes its 

 fibres with thofe of the fac, at the edge of which it ends. 

 The cephalopoda have eight conical feet, of different 

 lengths, arranged in a circle at the top of the head, round 

 the mouth. The animal can turn and bend them in every 

 diredlion, and faften itfelf to bodies by help of the cups 

 or fuckers with which they are furnifhed. The mufcles, 

 which perform their motions, are very numerous : they 

 may, however, be diftinguifhed into thofe that are common 

 to the whole foot, and thofe that are proper to the fuckers. 



Below the flcin we find a very thin mufcle, the fibres of 

 which are united by a loofe cellular fubftance. It accom- 

 panies the fkin in all its different fiiapes, and may, perhaps, 

 be regarded as a mufculus cutaneus employed to corrugate 

 the fkin, and give greater force to the mufcle fituated 

 within it, upon which it afts hke a girdle. Between the 

 feet, and under the fkin, which unites them at their bafe, 



two 



