VERMES. 



prefled without being diluted, its colour is a black violet ; 

 but it gives water the tint of claret wine. A fingle 

 aplyfia is capable of colouring in this way feveral buckets 

 of water. 



In fpirits of wine this liquor becomes of a deep green. 

 Some naturalifts reprcfent that the colouring liquor of cer- 

 tain animals of the genus murex comes out of the body 

 green, and changes to purple by the aftion of light But it 

 may be fqueezed out of the murex brandaris of a perfeft 

 violet colour. 



Spinning Organs ( Filicres ) of acephalous Mollufca. — The 

 mufcles of falt-water (mytilus), the lini^ (oltrea lima, 

 Linn.), pernx (oftrea, Linn.), aviculae. and peftines, are 

 fixed to rocks by means of threads, which they make them- 

 felves. Thofe of the pinna are the moft celebrated, for 

 they have been aftually employed in manufactures. 



The matter, of which the threads are formed, is pro- 

 duced by a conglomerate gland, concealed in the body under 

 the bafe of the foot. The latter, which has more or lefs 

 refemblance to a tongue, with a groove along its under 

 furface, feizes the rifcous matter at the orifice of the ex- 

 cretory tube, draws it out, and models it in the groove. 

 It fixes the end, ftill foft, to a rock, and returns to the 

 orifice, to find the materials of another. Reaumur has mi- 

 nutely defcribed the procefs, in the Memoirs of the Royal 

 Academy of Sciences for 1 710, from which we have taken 

 the following particulars. 



" From the root of this kind of tongue, or the part where 

 it is attached to the body of the animal, feveral threads are 

 obfervcd to proceed to fome neighbouring fixed object, and 

 thus *tach the animal in its lituation. They are about 

 equal in fize to a pig's bridle ; vary in length from one to 

 two inches, and pafs out of the (hell at the^ part where it 

 naturally opens. Stones, fragments of (hells, and very fre- 

 quently the (hells of other mufcles, are the objefts to which 

 thev are fixed : hence we often find large alTemblages of 

 thefe animals adhering together. I have fometimes reckoned 

 more than 150 threads employed in faftening a fingle mulcle : 

 as they take different direftions, we may regard them as fo 

 many cables keeping the animal firmly anchored. 



" Having detached feveral, I incloled them in boxes, and 

 put them in the fea : in a few days, they were attached to 

 the fides of the veffel, and to each other. I placed others 

 in velfels of fea-water, and obferved their proceedings. In 

 a (liort time they opened their (hell, and thruft out the part 

 already defcribed, which I have compared to a tongue. 

 They elongated and then (liortened it, and thus ftretched it 

 out farther : they would at laft extend it to two inches in 

 length, and then feel about with its extremity, as if to re- 

 connoitre the ground. After thefe preludes, they fixed it 

 for a time in one fpot, and then withdrew it quickly, cann- 

 ing it back completely into the (hell. I now difcovered 

 that they were fixed to the fpot by a thread. The repeti- 

 tion of this manceuvre multiplied the threads, until they 

 were fufEciently numerous to fallen the animal. The new 

 threads thus formed were whiter and more tranfparent than 

 thofe which had exiHed for fome time." P. 1 14, et feq. 



When a thread has been formed, the animal feems to try 

 its ftrength, and fometimes it gives way. They will fix 

 themfelves to the furface of glafs. They do not form more 

 than four or five threads in a day. P. 122. 



M. Reaumur could not difcover whether they have the 

 power of detaching themfelves, after being once fixed. 

 The youngeft mufcles fpin thefe threads, fuch even as are 

 fmallcr than millet feeds. The threads give way in time, 

 either from the repeated (hocks to which they are expofed, 

 or from an alteration in their texture by time. P. 123. 



The pinnsE are very large animals, the valves of their 

 (liells meafuring one or two feet, attached to rocks, &c. ii> 

 a manner fimilar to that of the mufcles, except that the 

 threads are longer and more numerous. They alraoil equal, 

 in finenefs and beauty, the filk fpun by the filkworm : hence 

 the French name of coquille porte-foie, and the ancient 

 name of barba byflina applied to this prodiiftioii, which has 

 been generally called the beard oi the animal. It has aftually 

 been manufaftured in Sicily, and other parts of the Medi- 

 terranean, into gloves and other articles, which exaftly re- 

 fembled filk. As the individual threads are fo fine, their 

 number is immenfe. Ibid. 



In the Memoirs for 17 17, Reaumur fpeaks at greater 

 length of the pinna or jambonneau, and the filk threads 

 which attach the animal to furrounding objefts. Thefe 

 animals are filhed in the Mediterranean, in from fifteen to 

 thirty feet of water. The tuft of filk is attached, as in the 

 mufcle, immediately to the animal's body, and palTes be- 

 tween the two valves, at four or five inches from the fmall 

 end of the (heU, in large pinna;. As they are torn up with 

 an iron hook, you cannot be fure of feeing the whole length 

 of the faftening ; but Reaumur has found it feven or eight 

 inches long, and weighing three ounces. The fpinning 

 organ is about two inches long in the dead animal, and mult 

 admit of extenfion to fix or feven inches in the living, to 

 form threads of the length we meet with. The end of the 

 filk palTes into a conical bag, which contains four mem- 

 branous plates, and an equal number between them of thin 

 filk plates, made of fine filk intricately interwoven. The 

 filk faftening of the animal is fecrired to the latter. Ob- 

 fervations fur le Coquillage appelie Pinne marine, ou Nacre 

 de Perle, &c. 



On the fubje(ft of the remarkable power, poffefled by 

 many animals of the lower orders, particularly in the genus 

 medufa, of producing hght, fee the article LtGHT. 



The fource of that Angular property, which many me- 

 dufa polTefs, of imparting a burning fenfation to the (kin, 

 like that produced by the common nettle, (whence their 

 names of urtica marina, fea-nettles, &c. ) is not known. 

 It may be in fome fluid fecreted by the animal. 



We may obferve, in general, of all the fecretions in the 

 lower orders, including the purple matter and filk, tlie 

 biliary fluids, the luminous and ftinging particles, the cal- 

 careous matter of (hells, &c. that they are produced in 

 ftruftures much lefs complicated, and in animals much lefs 

 perfeAly organized, than the analogous piodufts of the 

 vertebral divifion. 



We cannot pretend to give a complete enumeration of the 

 works, from which information may be derived on the fubjeft 

 of the preceding article ; but we (hall mention a few of the 

 moft important. 



On the aratomy of the lower orders, fcience is moft 

 deeply indebted to the learned, acute, and indefatigable 

 Cuvier, who has contributed more than all others together 

 to our accurate knowledge of thefe clafTes. His " Legons 

 d' Anatomic comparee" contain the refults of moft of his 

 labours ; and the greater part of our defcriptions is derived 

 from that work. He has alfo pubii(hed numerous excellent 

 papers, accompanied with very beautiful and valuable en- 

 gravings, on the anatomy of feveral genera of m.ollufca, in 

 the Memoires du Mufeum National d'Hiftoire Naturelle. 

 They are as follow : 



Memoire fur 1' Animal de la Lingule (Lingula anatina, 

 Lamarck); torn. i. p. 69. 



Memoire fur la Bullsea aperta (Lamarck), Bulla aperta 

 (Linn.); torn. i. p. 156. 



Memoirie fur le Clio bcrealis j torn. i. p. 242. 



Memoire 



