230 



MUSEUM OF ANIMATED NATURE. 



[Cowries. 



assume more the character of the genus, as the 

 outer hp be)(ins to be inflected or rather thickened, 

 and approaclies nearer the perfect appearance ofthe 

 species as the second coat of colour is deposited ; 

 but it differs from the perfect shell in the want of 

 thickness, in the spire being more distinct, and in 

 the «vant ofthe dorsal line, which is usually diMinct 

 in the third or perfect slate, when the last coat has 

 been deposited (by the rellected mantle), and the 

 aperture is more plaited on both sides. The colour- 

 ing, or at least tlie disposition of colourings in the 

 cowries, is a much more certain characteristic of 

 species than either the general outline of form or 

 size, the latter of which is exceedingly various. In 

 this family 1 have often observed full-grown spe- 

 cimens of C. Arabica from one to three inches long. 

 This )>eculiarity is attempted to be explained by 

 Lamarck and others, who assert that when the 

 animal has formed a complete shell, as it has not the 

 faculty of enlarging its size, it is obliged to quit its 

 shell and form a new one, in the same manner as 

 the Annulosa cast their skins, and by tluit means the 

 same animal forms many shells ; but I believe there 

 is not the slightest ground for this notion." Figs. 

 27o0, 2731, and 2702 display the Cypisea exan- 

 thema in various stages. Fig. 2750 is the Young 

 in the first stage : a, tne back : b, the front view of 

 the same, showing the columella and the thin edge 

 of the outer lip. Fig. 2751, the same at more ad- 

 vanced periods: c exhibits the back; the npex is 

 already sinking, anil the thickened lips are formed ; 

 (/ shows the shell still more advanced; the mantle 

 has begun to secrete the enamelled spotted layer on 

 the side, hut the transverse stripes are still visible. 

 At Fig. 2752, « shows the perfect shell, back view ; 

 all traces ofthe transverse stripes are lost under the 

 enamelling of the thickened spotted coat :_/" repre- 

 sents the opposite view of the same, from which the 

 alteration in the character of the aperture may be 

 appreciated. 



The growth of the shell, however, in the cowry, so 

 as to accord with the growth of the moUusk, is a 

 subject of some difficulty, and has engaged the at- 

 tention of many naturalists. Dr. Fleming, in his 

 'Philosophy of Zoology' (vol. ii. p. 403), after 

 observing that the formation of porcellaneous shells 

 must take place in a different manner from those 

 which evidently increase in size by the application 

 of fresh layers of shelly matter to the margin ofthe 

 mouth, goes on to say: '' If we attend to the form 

 of a young shell belonging to the genus Cypiaca of 

 LinncBus, we may perceive that an addition of shelly 

 matter to the margin ofthe aperture, in the manner 

 in which it is applied to other shells, would not en- 

 large the cavity, but completely close the aperture. 

 The increase of the shell (accompanied by a corre- 

 sponding increase of its inhabitant) must take place, 

 therefore, eilher by absorption of the accumulated 

 shelly matter ofthe mouth, and an elongation in the 

 direction of the greatest curvature of the shell, or 

 the old shell must be thrown off, and a new one pro- 

 duced suited to the size ofthe animal. The former 

 supposition has not been entertained ; the latter is 

 now generally received by naturalists. The inner 

 coat of such shells appears to be a transudation 

 from the body of the animal, and the outer one to 

 be laid on the surface by the loose reflected lobes of 

 the cloak (mantle). In many other shells, portions 

 of matter more compact than the other parts may 

 be observed spread on the pillar, and applied to the 

 margin of the mouth by a similar process. Mr. 

 Piatt, in support of Rdaumur's opinion that shells 

 are formed by juxtaposition, against the objections 

 of Mr. Poupait (• Phil. Trans./ vol. liv. p. 43), er- 

 roneously considers the different sizes of the Cypraese 

 as depending on the thickness of the shell increasing 

 according to age, without admitting a corresponding 

 increase ol'the contained animal, or of the cavity for 

 its reception. If we turn to Figs. 2750, 2751, 27.52, 

 illustrative of the young and adult of Cypraea exan- 

 thema, we shall find an increase of size in every 

 direction, nor do we clearly see how any addition 

 to the outer edge of the shell (at 6) will bring it to 

 the volume of the whorl seen aiy. 



Again, if we turn to the Money cowry (Fig. 2759), 

 it would seem as if the outer lip of the young, in 

 order to assume the figure presented by the same 

 part in the adult shell, must be first absorbed and 

 iheii remodelled, for a mere addition to its margin 

 would only tend to close the aperture ; and besides 

 this, we have then to account for the increase ofthe 

 shell in every direction, for it will be observed that 

 the proportions of the young shell viewed on the 

 back, and the figure of the columellar portion of 

 the front of the young shell, are but little dissimilar 

 from those ofthe adult shell, only upon a smaller 

 scale. The convexity of the back in the adult is 

 not only apparently larger, that is from increased 

 external depositions adding to the thickness ofthe 

 shell, but really so, corresponding to the room re- 

 quired internally for the accommodation of the 

 increased mollusk. Now we cannot account for the 

 increase of the boss of this shell excepting on the 



supposition of a gradual internal absorption on the 

 one liand, and a co-ordinate secretion and deposition 

 of fresh matter on the other ; or, on the circumstance 

 of the young animal quitting its shell when straitened 

 for room, and investing itself afresh. 



Look again at Trivia Europxa(Fig. 27C5;a, adult ; 

 b, young), in which, excepting in the form of the 

 outer lip, the young and adult closely resemble each 

 other in figure, though they differ in size. How, while 

 keeping the proporlionsalieadyattained, islhoyoung 

 shell to acquire the size of the adult ? Surely by no 

 additions to the margin of the outer lip and its con- 

 setiuent inflexion, for the outer lip has to extend 

 outwardly, in addition to the thickening and in- 

 flexion of its edge, and the orifice is nut at the 

 same time to become contracted, but rather propor- 

 tionally enlarged. Unless, indeed, we are prepared, 

 with some naturalists, to consider a change of shell 

 to lake place, we must have recourse to the ope- 

 rations of gradual absorption and deposition ac- 

 cording to the growth of the animal, and the 

 necessity of enlargement in any given part of the 

 shell more than in another part. 



These observations, however, must be understood 

 only as bearing upon young shells which closely 

 resemble those of the adult in figure, with the ex- 

 ception of the involution of the outer lip, but yet 

 are far inferior in size ; at a very early stage the 

 whorls of the Cypraea evidently increase in size in 

 the ordinary way, as in the olive-shells, volutes, &c., 

 by additions of shelly matter to the outer lip, and at 

 this period the shell of the Cypraea closely resembles 

 that of the Olive, but this resemblance by degrees 

 disappears, and that before the full growth of the 

 shell IS accomplished. We learn that Mj-. Gray has 

 recently observed that sometimes, though rarely, the 

 young shells of Cypraea, especially Cypraea Arabica, 

 have the inner edge of the outer lip thickened, and 

 furnished with a compressed sharp-edged series of 

 teeth. It is in such a case that we must look for 

 some other explanation of the mode of growth than 

 by mere additions to this lip. 



With regard to the mollusk of Cypraea, it may be 

 described as unisexual, of an elongated figure, 

 having the head distinct, with two conical or su- 

 bulate tentacula of some length, at the external base 

 of which are thetvvo eyes, sessile on small projections. 

 The mouth is vertical at the bottom of a small cavity, 

 and contains a lingual riband beset with tentacles, 

 and prolonged into the interior of the body. The 

 mantle is bilobcd, the lobes being very large, with 

 extended aliform edges in the adult, capable of 

 being reflected over the back of the shell so as to 

 meet on the mesial line. The foot is oval, thin, and 

 destitute of an operculum. 



The Cypraeidae are very widely spread, being 

 found in the seas both of the old and of the new 

 world ; it is, however, in the hotter latitudes that they 

 are most numerous, and display the greatest deve- 

 lopment in point of size and the richest colouring. 

 A few species occur in our European seas. In their 

 habits the Cypraeidtc are littoral, tenanting beds of 

 sand, or creeping under large stones or rolled masses 

 of coral. 



In the ' Zoological Journal ' will be found a 

 monograph of the cowries, by Mr. Gray, which, 

 together with the seventeenth number of Mr. Sow- 

 erby's ' Genera of Shells,' may be consulted with 

 advantage. 



The cowries are divided into several genera and 

 subgenera, according to minor peculiarities in the 

 form and characters of the shell; and these genera 

 and subgenera in Mr. Gray's arrangement are again 

 subdivided into minor sections. The genus Cypraea 

 is subdivided into subgenera Cypraea, Aricia, and 

 Naria. 



In the first subgenus, Cypraea, the front of the co- 

 lumella is described as broad and deeply impressed ; 

 the shell is mostly smooth. The section a of this 

 subgenus is thus characterized : — shell smooth, colu- 

 mellar pit transversely ridged, teeth ofthe inner lip 

 generally long. (Gray.) As examples, Mr. Gray 

 enumerates twenty-seven species, among which are 

 Cypraea Aurora (the Morning Dawn, or orange 

 cowry), the Cypraea princeps, the Cypraea tigris, and 

 the following. — 



2753. — The Map- Cowry 



{Cypraa mappa). n, the shell seen from above; J, 

 seen from below. 



In this elegant species the shell is ovate, more or 

 less ventiicose, varied with deep brown or yellow 

 lines and spots. The dorsal line is laciniated ; the 

 margin is thick spotted with black; teeth yellow. 

 The map-cowry is extensively spread in the Indian 

 seas, and is subject to considerable variation. 

 Among these we may notice the rosy variety and 

 the dark variety, from the Pearl Islands; the citron 

 variety and the dwarf rich-mouthed variety, from the 

 Mauritius. 



The young shell is of a fawn colour, with obsolete 

 spots and dashes. 



In section /3 the shell is smooth, the columellar 



pit nearly smooth, the teeth of the inner lip short 

 and indistinct. Of fifteen species enumerated by 

 Mr. Gray, we select the following: — 



2754. — The Mole-Cowry 



(Cypraa talpa). Sardonyx cowry of Gray. 



In this species the shell is oblong-ovate, subcy- 

 lindrical ; its colour is yellowish, with three darker 

 bands; the subangular base and teeth are browu or 

 black ; the mouth pale. A variety of this species 

 occurs which has received the title exuslus ; it is 

 ^shorter in form and darker coloured, with the teeth 

 smaller and closer. 



In section y the shell has the back warty or tu- 

 berculous, rarely smooth ; and the base on each side 

 of the aperture is ridged. 



Three species are assigned by Mr. Gray to this 

 section, of which we may select the Vetch-Cowry as 

 an example. 



2755. — The Vetch-Cowry 



(Ci/praa cicercuh). a, the shell seen from above; 

 b, seen from below. 



The shell is subglobose, with a dorsal groove and 

 scattered tubercles; the base is partly grooved. 

 The general colour is yellow, dotted with brown; 

 four spots are on the base. 



A larger variety, as it is generally considered (C. 

 globulus), is destitute of the dorsal furrow, and is 

 more oblong and smooth. 



A fourth section, S, is characterized as having 

 transverse ribs. 



To this section Mr. Gray refers two species, of 

 which one, the Cypiaea rugosa, Broderip, is fossil ; 

 the other we have selected by way of example. 



2756. — Children's Cowry 



{Cypraea Childreni. Gray), a, the shell seen from 

 above ; 6, from below. In both views the transverse 

 striae are to be distinctly seen. 



A fifth section, €, is distinguished by the shell 

 having longitudinal and transverse ribs. One species 

 only is noticed, viz. Adansou's cowry. 



2757. — Adanson's Cowey 



(Ct/prcea Adansoni, Gray). This rare species is 

 somewhat pear-shaped, and of a white colour mottled 

 with brown. Mr. Gray gives the Pacific Ocean, 

 with a query, as its locality. 



The next subgenus is Aricia; it is characterized 

 by the front ofthe columella being flat or nearly so, 

 and the back of the shell smooth. 



The fiist subdivision, a, of this subgenus has the 

 margin of the shell pitted on the upper edge. Mr. 

 Gray enumerates fourteen species, of which the 

 blotched cowry is one. 



2758. — The Bi.otcheu Cowby 

 (Aricia guttata). Cypraea guttata. 



This I are and beautiful shell is brown, spotted 

 with a paler tint ; the base and margin are white, 

 with brown ridges. Mr. Gray gives the Red Sea, 

 with a query, as its locality. 



Subdivision 0. In this group the margin is entire, 

 and the teeth of both lips are extended more or less 

 over the base. The species enumerated are thirty- 

 seven. 



2759.— The Money Cowry 



{Aricia moneta'). Cypraea moneta. 



It is this species which is used in some parts of 

 India and Africa as money, a circumstance to which 

 we have already alluded. The shell is yellow, or 

 white with a yellow ring ; the margin and base are 

 tubercular ; the teeth of the inner lip moderate. 



Some varieties occur destitute of a yellow ring, 

 and with the margin and base less tubercular. 



The young are whitish, with two dark bands, and 

 in this state are the Cypraea icterinia of Larnarck. 



lleferring to the figure, a, a leprtsent the adult 

 shell in two views ; b, b, the young, also ia twe 

 aspects. 



Subdivision y is characterized by the margin 

 being entire, the teeth of the inner lip very small, 

 forming a slight ridge ; the front of the columellar 

 lip slightly concave, produced and toothed inter- 

 nally. Two species are enumerated. 



2760. — The straitened Cowry 



{Aricia angustataX Cyproea angustata. 



This cowry, which is brought from the coasts of 

 New Holland, is of a whitish brown colour, minutely 

 dotted with brown ; the base is white, the margin 

 closely dotted with black ; the ends blackish. 



The next subgenus is Naria, distinguished by the 

 front of the columella being narrow, and dilated into 

 a sharp-toothed lidge. The shell is smooth. A 

 single sjiecies only is referred by Mr. Gray to this 

 genus. 



2761. — The Freckled Cowry 



{Naria irrorata). Cypraea inorata. 



This small species is brought to Europe from the 

 South Seas : the shell is ovate, and of a purplish 



