CONCH OLOGY, 



appear externally, but lie latent or quite hidden within 

 tlie body of the fliell : Turbinata, volulse apice non emi- 

 iiente, vel clavicula intus rei;ondita. The nautiii aie of 

 a ch inibered ftiu<.'>ure ; the partitions uf the cells or 

 chambers being coiicave-tronvex roundifli plates. How- 

 ever, there are foflll kinds with foliaceoiis futures like the 

 ammonitse; which implies, that all the fpecies have-not 

 fucn regularly round partitions : and, indeed, Breynius, 

 on this account, divides the nautili into two orders ; thole 

 with concave-convex femilunar diaphragms, and thole 

 with jagged or finuated diaphragms. 



TJie paper nautile, though claiVtd by moft aiithors as 

 a nautilus, is of a different genus, as not being of a cham- 

 bered ftiutlure. Authors make two varieties of the Eall 

 Indian or pearly kind, viz. the umbilicated and the iion- 

 limbilicated ; but Gmelin confiders them as the hme ani- 

 mal, and places them both under the fpecific name of 

 ftiiuttlas ponipilius. This is by feveral authors erroneoully 

 called nautilus Gracoriim: whereas the nautilus of the 

 Greeks was the paper nautilus, or argonaut. 



The animal belonging to this fliell is laid to inhabit 

 only the uppermolt or open chamber, which is nuich 

 larger than the reft. The others remain empty, except 

 that the pipe, or fiphnnculus, which communicates from 

 chamber to chamber,' is filled with an appendage or tail 

 of the animal, like a gnt or firing. Tlie fiphnnculus is a 

 dilatable tube under the command of the animal. When 

 it is dilated," like the fwimming-bladder of a fiih, it ren- 

 deis the nautilus buoyant. When it is contrafted, the 

 fifli and fliell fmk, and jull to fuch a degree as the prefent 

 occafions of the animal require. 



Thtieare two remarkable foifil kinds of nautili yet un- 

 difcovered in a living ftate, viz. One about the fize of a 

 pippin, quite pyritical, without the flighted veiliges of 

 the natural fliell. It is deeply umbilicated, has fine folia- 

 ceous futures in feveral parts, and is thickly and finely 

 ridged acrofs from fide to fide ; the ridges not Itraight, 

 but curved, the curvature tending downwards, or from 

 the mouth. The other, a i'mail kind, with undulated fu- 

 tures, found in the liineftone of Derbyfliire, and in Ger- 

 many. 



The nautilus has been always efteemed, as well for the 

 elegance of its Iheil, as for the beautiful mother of pearl 

 V'bich it produces. Fig. 9, in the fecond plate of con- 

 chology, exhibits Knorr's correijt drawing of this fliell, in 

 its natural Itate. The ground-colour is a yellowifli-white, 

 appioaching, at the extremities to a light orange. In 

 the center it is radiated with flame-colour, from whence 

 proceed ftriated irregular bands of deep red in all direc- 

 tions. The infide is lined with moft beautiful pearl. 

 The black which rifes over the fpiral concamerations is 

 perfeftly natural, and is occafiotied by a mucous matter 

 which the animal throws out, fimilar to tlie cuttle-fifti. 

 The bottom of the fliell is rounded in a beautiful foim, 

 and mealiires about a foot and a half in diameter; and is 

 of the thicknefsofa half-crown piece. It inhabits the 

 Indian ocean, and is found on the iliores of Africa, parti- 

 cularly near the Cape of Good Hope, where, quickly af- 

 ter a ilorm, they are feen to fwim about in conliderable 

 numbers, and are then taken only by the molt expert 

 fifliermen. 



The fuperb cordated ftru6f ure of the interior part, with 

 its materials of orient pearl, has induced us to give the 

 Conchology-Piate HI. for the more perfeit illuftration of 

 this celebrated fliell. Fig. i, rtprefents the fliell with its 

 exterior lamina or covering taken off, to ftiew the beauti- 

 ful pearl of which the interior fubllance is compofed. A 

 filvery luftre, with undulating waves, on which a pale de- 

 licate red exjiands iifelf, and at every movement changes 

 to a ditTerent colour, gives this fliell a magnificent ap- 

 pearance. Formerly artills fpent much time in woiking 

 tliefe fliells, to increale their beauty, either by decora- 

 tions in bafs-relief; or by fimply^engraving lines, which 

 they rubbed over with various tints. Hence we often 

 find thel'e Ihells ornamented with emblematical figures, 

 4 



fuch .IS the bacchanals, hunting, fiflling, foliage, fymbols, 

 arms, crefts, and other decorations. Sometimes they are 

 mounted with gold or filver, and converted into drinking 

 velfels; for tiiey will hold more than a quart. In the fi- 

 gure there is a large biown fpot in the middle of the 

 fliell, which it is neceflary to explain, becaufe it lurijilhes 

 a charafter, by which the nautile is diitinguiflied froin 

 the cornu amnaonia. In all the latter, the circles are ap- 

 parent in the fame place near the center of the firff 

 whirl; but the nautile has the (hell clofed. Fig. 2, re- 

 prefents an infide view of the fanie fliell, whereby the cor- 

 dated work, and ail the partitions, may be feen, even to 

 the fmallelt, which is in tlie center. It is' to that only 

 that the animal is faflentd by a tendon. This tendon 

 pafl'.'s through all the divifions, in a liphon, fallrened in 

 the middle of the partitions, quite to the principal one, 

 which is the largelf, and properly the animars abode. 

 The other partitions do not appear to be of much real 

 ufe to the fifti ; for it has never been found in any of 

 them. The flefliy pait, or'body of the animal, fills up 

 all the interior of the largeft chamber; but at the ap- 

 proach of danger, or when it perceives an enemy, it con- 

 tracts itfelf into a very fmall fold, and lies hid below the 

 ftiell. There may be fome doubt uhether the tendon 

 which palfes thrpugh the partitions, does not receive a 

 great part of tlie animal's interior fubftaiice on thefe oc- 

 cafions; which circuiirftance ieems necefiaiily to follow, 

 from the diminution of the body. 



Of KEVOLVED VNIVALVES. 



Revolved fliells are thofe whofe fpires are latent, or hid- 

 den within the body, and do not in any manner appear 

 externally ; fo that they have no clavicle or turban. The 

 nautilus pompilius is alfo a revolved Ihell ; but, being 

 more remarkable for its chambered ftru6ture, it is ar- 

 ranged in the preceding clafs. This divifion contains the 

 fixth family of the univalves, which Da Cofta forms into 

 three genera, viz. nuces or buUje, the pewit's eggs, or 

 dipping fnails; feniiporcellana;, or ftiells nearly relembling 

 the porcellains ; cyprese or poroellan<e, the cowries. 



BULLA, THE DIPPER, or. PEWIT'S EGG. 



The firft genus, or bullae, befides their common names 

 of pewit's eggs, and dippers, are alfo c:\\\iiAfe.a-niits. The_ 

 definition of this genus is as follows : they are moltly of 

 an oval fliape, and umbilicated at the bottom. The mouth 

 is veiy patulous, efpecially at tlie top.-for it narrows 

 greatly downwards. The lip is thin, fliarp, and naked, 

 or without any border or other work; and with a finall 

 facing or colamella lip on. the upper part ot the mouth. 

 The anangement of this genus is much coni'ufed in au- 

 thors, by their Iceining connexion with the two follow- 

 ing genera of femiporcellanje and cypreas. Lilter makes 

 them a genus of cowry, and calls it concka 'veneris haft 

 umbilicata. Grew and Buoiianni place it with the fnails. 

 Rumphius, v.ith his cochlea: glohofie ; Argenville, Da- 

 vila, and Meufchen, do the fame ; and, indeed, Linnsus's 

 genus of bulla includes the figs, turnips, &c..as well as 

 the dippers. Gualtieri makes it a genus preceding the 

 cowries, and following the paper nautilus.. 



The arrangement that Rumphius, Argenville, Li:i- 

 iia:us, Davila, and Meufchen, give them as cochle<e glo- 

 boCa;, or tuns, is very furpriling, and extremely errone- 

 ous; fince they have a very diifrrent efl'ential character, 

 though all have p.itulous or very large mouths. For the 

 nuces, o^ bullae, like the cowries, have no clavicle or tur- 

 ban, becaule their fpirts lie within their bodies ; whereas 

 the conchje globcfe, as the partridges, tuns, &c. are re- 

 ally turbinated fliells, and have a very fair and Hrong ex- 

 ternal clavicle ; but it is generally flattilh, or not mucii. 

 produced. Though there is a valt difference oi colourinsf 

 in the dippers, it feems, nrverthclefs, that they are only 

 varieties, and that this genus is not numerous. Tive 

 Conchology-Plate IV. exhibits IpeLimens of thcfe dip- 

 ping-fiiells, or pewit's eggs, from Seba. 



