CONCHOLOGY. 



'JO 



vifib'e there. This creature h wonderfully minute when 

 newly excluded from the egg ; but it grows to the length 

 of four or fix inches, and fometimcs more. Wlien the 

 bottom of a I'cifel, or any piece of wood which is con- 

 ftantly underwater, is inhabited by thefe worms, it is full 

 of fmall holes ; but no damage appears till the ouier parts 

 are cut a.w?.y : tlun their (lielly habitations come into view ; 

 in which there is a large fpace for inclofing the animal, and 

 furrounding it with water. Tliere is an evident care in 

 thcfe creatures never to injuie one another's habitations ; 

 by this means each cafe or ihell is preferved entire ; and 

 in (iicb pieces of wood as have been found eaten by them 

 into a fort of honeycomb, there never is feen a palVage or 

 communication between any two of the (hells, though the 

 •woody matter between them often is not thicker than a 

 piece of writing-paper. They penetrate fome kinds of 

 wood much more eafilv than others. They make their 

 way moft quickly into fir and alder, and there grew to 

 the greateft fize. In the oak they make lefs progrels, and 

 appear fmall and feeble, and their ihells are much difco- 

 loured. Since each of thefe animals is lodged in a foli- 

 tary cell, and has noaccef's to thofe of its own fpecies, it 

 has been matter of furprifc how they fhould increafe tofo 

 vafl a multitude. Upon diffeiiling them, it appears that 

 every individual has the parts of both fexes, and is there- 

 fore fuppofed to propagate by itfelf. Thefe lea- worms 

 appear to have the fame office allotted them in the w.y 

 ters, which the termites have on the land. They will 

 appear, on a very little confideration, notwithftanding 

 they are fo pernicious tofliipping, to be -molt important 

 beings in the great chain of creation, and plealingly de- 

 luonllrate tliat infinitely wife and gracious Power which 

 formed, and ftill preferves, the whole in fuch wonderful 

 Older and beauty; for, if it was not for the rapacity of 

 thefe and fuch animals, tropical rivers, and, indeed, the 

 ocean itfelf, would be choked with the bodies of trees 

 whicli are annually carried down by the rapid torrents, 

 as many of them would lad for ages, and probably be pro- 

 ihiflive of evils, of which, happily, we cannot in the pre- 

 fent harmonious ftate of things form any idea; whereas 

 now, beine; conl'umed by tliele animals, they arc more 

 eafily broken in pieces by the waves; and the fragments 

 ■which are not devoured become fpecifically lighter, and 

 are confequenlly more readily and more effedually thrown 

 on lliore, where the fun, wind, infers, and various other 

 inftruments, fpcedily promote their entire difTolution. 



The Sabella is a fimilar creature, the (hell of which 

 is tubulous, and formed of grains of fand cemented to- 

 ■gether and hardened invo a cruftaceous covering, bythe 

 mucous matter which ifiues from the included inhabitant. 

 There are twenty-five fpecies, of various fizes, from half 

 an' inch to nine inches long. Some of them inhabit the 

 Britith f.-as, the coalts of Norway and Greenland, and the 

 Cape of Good Hope ; others, of the larger fize, are found 

 in the Indian ocean, and in the South Sea; on the coalls 

 of America, and in the fait lakes of Thuringia. 



Gualtieri ranks the famous (hcU the wentleirap, or ftair- 

 cafe, with vermiculi : he gives for reaibn, that the fpires 

 of this (hell are mere loofe ones, not produced from, or 

 anyway connefled or fupported by, a pillar or columella, 

 running through the middle of the (hell its whoie length, 

 as is the conltant and true (hufiure of all turbinated 

 fliells. Davila places it among his vermiculares, without 

 giving any reafbn for fo doing. There are alio vermiculi 

 which hav/; concamerstions, or .arc divided into chambers 

 by a few or many tranfverie plates running acrols the 

 tiibe; but they arc feldoni regular, or fet at equidillant 

 intervals and are not pierced by a pipe or liphunculus, 

 that conmninicates from chamber to chambtr, fb as to 

 peiinit the fifli to penetrate more than one chamber or 

 inclolure at a time, in which particulars they eilentially 

 differ from the concamerateJ (liells. Belides, thcfe con- 

 cameralions do not feein conlfant to any particular fpe- 

 cies, and appear rather the clofing up, and delerting the 

 old phice of habitation of the iidi, when it augments its 



(hell; juft like the bottotn fpire* of a turbinated (hell, 

 which the anima. fills up as it grows bigger, and e.ilarges 

 it liabita on. The v r;i;icuii ar. freqi.:entiy foan.i \a 

 the foUil (tite; but we do not recoUeil any Ipecics, but 

 wiiat is known in a living (tate recent from the lea. 



DENTALIA, or TUSK-LIKE SHELLS, 



This family of fimple (hells is likewife of the terebellj 

 or piercer fpecies; but is (eparated from the preceding 

 genera, on account of the difference in its conformation. 

 The efTeutial charatter of this (hell is, that it is iiuiple, 

 tubular; of a regular, determinate, curved, conical, (li.spej 

 and open at both ends. This (hell is found from one to 

 four or five inches long. There ai-e twenty-one Ipecies, 

 which are natives of the Indian ocean, tlie Mediterra- 

 nean fea, the Englifh channel, and molt of the lea coafts 

 in different parts of the world. 



The Concliology-Plate I. exhibits different figures of 

 the vermiculi, or lea- worm (hells. Fig. i. A clufterof the 

 ferpula contO'tupUcata, from Knorr. Fig. 2. The large 

 green-furrowed dentale of the Eaft Indies. Fig. 3. Tha 

 Imooth yellowilh dentale of the Englilh fea. 



The patella, or LIMPET. 



This family derives its generic name from its refem- 

 blance to a little plate; like this utenfii, the limpets arc 

 for the moft part round, or oval, or approaching tnereto; 

 the part that contains the fifh is concave, fmooth, and 

 often finely waflied with colours. The fliell is more or 

 lefs conical; it has no contour, but the'rock or other 

 hard body to which it adheres, lerves as a kind of fecund 

 or under (hell, to preferve it from injury. On this ac- 

 count Aldrovandus and Rondeletius claffcd the limpets 

 among the bivalves; but in this error they have not been 

 followed by any other writer. The apex, or eye ot the 

 limpet, is either whole or perforated, and is feldom placed 

 exacSly in the middle of tlie (hell, but molt commonly in- 

 clines towards one end ; that is, taking it in its longeft 

 dimenfions. The rim of the (hell, which forms its bafe, 

 is likewile various, Ibmetimes without any proujinencies 

 or fmootb, fometimes \xjlth large ones or jagged, and 

 fbmetimes with (lits only, or crenated. Their external 

 furface is often rough and fcabrous, and their apices of- 

 ten impcrieff; for, moft of this family .adhering to the 

 rocks, they are much expofed to the fun during ebb, and 

 to all the violences that render dead fhells unacceptable 

 to the curious. Though it commonly happens, that the 

 fhells molt remarkable for the brilliancy of their colours 

 are of the fimpleft form, as the nerits, olives, volutes, &c. 

 yet this tribe feems an exception. It is true there are 

 confiderahle numbers that have very lively colours; yet, 

 in general, they abound with lefs variety than moft otiicr 

 (liells. In fome parts of England the limpets have ob- 

 tained the name oi nipple-fhelts ; becaufe its convexity ter- 

 minates in a kind of papilla near the center. 



The limpets are very numerous, confifting of no lefs 

 than 238 fpecies, which Da Cofta divides into three ge- 

 nera of (hells, viz. I. Whole or entire limpets, (patella 

 •vertice inlegro,) or that are not perforated or open at the 

 top. 2. Chambered limpets, (patella- c-jncanurata- J':-ve 

 cnvitate fiylo interna doiiaia.) 3. Pierced or perforated 

 limpets or mafks, fpatelt,^ ivertice pcrfarato,) that have* 

 their tops perforated with a hois pierced quite through 

 the Ihc-ll. The firft genus, or whole liiiii st, is very nume- 

 rous. The iecond, or chambered liin pi: t, has many fpe- 

 cies : but the third genus, or perforated limpet, or mafks, 

 has but few fpecies. Europe, however, affords butveryfew. 

 The finelt and largelt are from the Eaft Indies and Africa, 

 efpecially from the Cape of Good Hope. America has 

 many of the chambered and fmaller kinds : and late dit- 

 coveries have brought Ibme large and fine limpets from 

 the Streights of Magellan and the South Sea. 



Thefe are all the notices that occur relative to the re- 

 cent limpets, or thofe known from fe.i. But there are 

 m.-»i>y (ollil (liells which are not yet diicovered ot known 



in 



