Peristomians.] 



MUSEUM OF ANIMATED NATURE. 



215 



The Navicellae, of which a limited number of 

 species only is known, are fluviatile in their habits, 

 and are natives of the Indian Archipelago. 



Referring to Fig. 2695, a represents the animal 

 in the shell, seen from below ; b is the operculum. 



2696. — The Black-lipped Natica 



{Natica melanostoma). The Naticae are extensively 

 spread in the warmer seas, and especially those 

 within the tropics; they are abundant also along 

 the coast of New Holland. 



The present species was found by MM. Quoy and 

 Gaimard, at the depth of several fathoms, near 

 Torga and the Molucca Islands : other species were 

 seen creeping near the shore on rocks and sea-weed, 

 and have been taken at various depths, from the 

 surface to that of forty fathoms, on muddy banks in 

 aestuaries and tidal rivers. 



The shell of Natica melanostoma is thin, oval, 

 convex, but depressed ; the spire is slightly promi- 

 nent ; the colour is white zoned with yellow ; lip 

 blackish brown. The operculum is membranous 

 and of a deep chestnut. 



Referring to Fig. 2696, a represents the shell 

 with the animal seen from above ; b, the animal out 

 of the shell ; c, the operculum. 



We now turn to a group of fresh-water shells, 

 constituting a family termed Peristomians in the 

 system of Lamarck, containing the genera Valvata, 

 Paludina, and Ampullaria, but which are referred 

 by Cuvier to the Turbinidae. M. Deshayes indeed, 

 commenting upon their organization, says, "It is 

 evident that the genera which it (the Peristoraian 

 family) contains closely approach to those of the 

 family of the Turbos ; it would therefore be proper to 

 place the Peristomians in the neighbourhood of the 

 Turbinaceans, and to arrange them near the family 

 of the Neritaceans, which has certainly less direct 

 affinities with the Turbo family." Mr. Swainson 

 regards these genera as forming, with some others, 

 a subfamily of Turbinidae. 



2697, 2698.— Thk Valvata 



{Valvata piscinalis). In the genus Valvata the 

 shell is discoid and umbilicated, with the whorls 

 rounded and distinct ; the aperture is circular, and 

 the operculum horny. The mollusk has a distinct 

 bead, prolonged into a sort of widened proboscis ; 

 the tentacles are long, with sessile eyes at the pos- 

 terior side of their base. It would appear that the 

 genus has hitherto been found only in Europe and 

 America ; about six species are known. 



The Valvata piscinalis inhabits the ponds and 

 rivulets of the British islands and the adjacent con- 

 tinent. It is a minute shell of elegant contour. 



At Fig. 2697, a represents the animal and shell of 

 the natural size ; 6, magnified. 



At Fig. 2698, a represents the shell of the natural 

 size ; b and c, magnified in two views ; d, the oper- 

 culum enlarged ; e, glutinous masses of eggs on a 

 leaf ; /, a mass of eggs enlarged. 



2699.— The Minute Paludina 



{Paludina parmda). In the genus Paludina the 

 shell is conoid, with the whorls of the spire rounded ; 

 the aperture is oval ; the operculum horny. 



The mollusk is furnished with a proboscidiform 

 A mouth ; the tentacles are conical, elongated, and 

 Ij contractile ; the foot oval, with a marginal furrow 

 at its anterior part. 



The PaludinsB have generally delicate shells ; the 

 form is extensively spread ; and species have been 

 found in Europe, Asia, Africa, and America. The 

 European are the inhabitants of temperate latitudes. 

 M. Deshayes observes " that the greatest number of 

 the species live in fresh waters, and that they are 

 met with in a great number of localities on the 

 earth's surface. They appear nevertheless to be 

 more common in the northern than in the southern 

 hemisphere." Some small species, he adds, live in 

 brackish waters, where they are found in great 

 abundance. 



The number of recent species given in the tables 

 of M. Deshayes amounts to twenty-five ; and of these, 

 three are also found to occur in a fossil state in ter- 

 tiary formations. Referring to Fig. 2699, a repre- 

 sents the animal and .shell, in a side view, magnified ; 

 b, as seen from above. 



2700. — The Viviparous Paludina 

 {Paludina vivipard). Helix vivipara, Linnaeus. 

 This species, which is abundant in the rivers and 

 fresh waters of our island, as well as of the conti- 

 nent, was regarded by Linnaeus as a Helix, but 

 Miiller withdrew it from that genus and united it to 

 Nerita. This error was afterwards rectified by 

 Lamarck, who, aided by the anatomical researches 

 of Cuvier, established the present genus and as- 

 assigned to it the proper situation. The shell of this 

 species is conoid, with rounded whorls, and dia- 

 phanous; it is smooth and generally of a greenish 

 Colour, with two or three purplish bands along the 

 turn of the whorls. 



What is very singular in the history of this spe- 

 cies is, that it produces living young, clad in a deli- 

 cate shell. 



In its habits it closely resembles Liranaea and 

 Planorbis. Fossil shells of this species occur in the 

 Weald clay and Tilgate beds, as well as the lower 

 divisions of the Hastings deposits (the Ashburnham 

 beds). 



Referring to Fig. 2700, a represents the shell of 

 an adult with young shells in it ; 6, the operculum ; 

 c, the young shell before exclusion. 



We now proceed to the genus Ampullaria, con- 

 taining the apple shells of collectors. 



In this genus the shell is globular, ventricose, and 

 umbilicated, furnished with an epidermis ; the spire 

 is very short, and the last whorl larger than all the 

 rest put together. 



The aperture is oval. The operculum is horny 

 or shelly. The mollusk has a large, shield-formed, 

 delicate foot ; the head is flattened, and terminated 

 anteriorly by two buccal tentacles ; there are be- 

 sides two very long tentacles supporting at their 

 base the eyes raised on peduncles. There is a long 

 respiratory tube or siphon, projecting to a consi- 

 detable distance, formed by the mantle, but im- 

 pressing no furrow on the lip of the shell. The 

 branchial cavity is very extensive, and the upper 

 boundary is doubled so as to form a great aquiferous 

 sac. Habits fluviatile. 



The Ampullariae frequent the lakes and rivers of 

 warm climates. Species of very large size have 

 been found in Asia, Africa, and America, and espe- 

 cially in the southern portion of the latter. Olivier 

 states that one is found in Lake Mareotis in com- 

 pany with marine shells. 



These fluviatile shells were arranged by Miiller 

 in his genus Nerita; and Linnaeus classed some 

 under the genus Helix. 



2701. — The Doubtful Ampullaria 



{Ampullaria dubia). The animal is represented 

 creeping : a is the operculum ; b, the right siphon ; 

 c, the left siphon. 



The same species is represented at Fig. 2702, so 

 as to show the lower side of the foot ; the animal 

 appears in the act of ascending to breathe, and with 

 the respiratory siphon protruded, a is the oper- 

 culum ; b, the right siphon ; c, the left siphon. 



2703. — The Ram's-Horn Ampullaria 



{Ampullaria comu arietis). Ceratodes fasciatus, 

 Guilding. a represents the animal creeping; b, 

 the animal in a supine position ; a, the operculum ; 

 b, the right siphon ; c, the respiratory siphon ; c, 

 the head, tentacles, eyes at their base, and expan- 

 sions at the side of the neck. 



2704. — The Globose Ampullaria 



{Ampullaria globosa). This species is said by Mr. 

 Swainson to be an inhabitant of the rivers of India. 

 The shell is represented as having the mouth closed 

 by the operculum. In this species the margin of the 

 aperture is thick and grooved. 



Ampullaria; have at various times been brought 

 alive to Europe. An able naturalist informs us that 

 the first, as it would seem, were sent to Paris, by 

 M. Caillaud, from the Nile. We learn that that 

 naturalist, during his voyage to Meroe, collected 

 several Egyptian " mollusca, which he distributed 

 generously among collectors. One correspondent 

 had been anxious for the fluviatile mollusks found 

 in the Nile. The person employed to collect these, 

 after having gathered a large quantity of river mol- 

 lusca, among which were some living Ampullariae, 

 put them all into a box of bran (son). This box 

 was delayed on its road by the operation of the 

 quarantine laws for four months, and, when it reached 

 M. Caillaud, was in such a state, from the putre- 

 faction of the greater part of its animal contents, 

 that he hastened to throw the whole into the water. 

 To his no small surprise, he found, a few hours after, 

 the greater part of the Ampullariae, which had been 

 shut up with this mass of putrefaction, quietly 

 creeping about upon the mud. He gave many in- 

 dividuals to M. Deshayes, who kept them alive from 

 four to five months. The latter zoologist remarks 

 that, since that communication, Mr. Sowerby, in the 

 ' Zoological Journal,' and M. Quoy, in the ' Zoology 

 of the Astrolabe,' have given the figures of many 

 other species of Ampullariae, several of which have 

 been brought alive to Europe. We know of no 

 other figures of Ampullariae in the ' Zoological 

 Journal ' than those illustiative of a paper by the 

 Rev. Lansdowne Guilding. 



On the 29th of October, 18.33, Mr, Cuming, so 

 well known for the great additions which he has 

 contributed to our knowledge of the mollusca by 

 his collections from the west, and who has since 

 been employed in the same laudable pursuit in the 

 east, to the great enrichment of this department of 

 zoology, brought to Mr. Broderip a specimen of Am- 

 pullaria globosa, expressing his opinion that it might 

 be alive. Mr. Broderip immediately placed the speci- 



men in a deep dish with some earth at the bottom, 

 which was covered with New River water, and 

 set it before the fire. On the 29th the animal 

 gave no sign ; but on the 30th it came forth and 

 soon showed tokens of vigorous life. It was after- 

 wards removed into a globular glass vase, such as 

 is used for gold and silver fish, with a good layer of 

 earth at the bottom. The water and earth were 

 changed periodically, and the animal continued to 

 live in apparently good health for many weeks. Its 

 death was probably occasioned by the difficulty of 

 resisting the low temperature of the long cold 

 winter nights, where there were no stoves, in short 

 nothing beyond the ordinary fires of a dwelling- 

 house. The specimen is now in the museum of the 

 Royal College of Surgeons. 



M. Deshayes proceeds to observe that it became 

 an object of inquiry how aquatic animals, unable to 

 respire except by means of a pectinated branchia, 

 could remain alive so long out of the element ap- 

 parently necessary to their existence. Neariy all 

 the persons, he remarks, who occupied themselves 

 with this phenomenon, thought that the animal on 

 retiring into its shell carried with it a certain quan- 

 tity of water, which could not escape owing to the 

 retention of the operculum, which closes the aper- 

 ture with great exactness. Others thought that the 

 humid air carried upon the branchiae was sufficient 

 to keep up the respiratory action. " Wishing to 

 know," continues M. Deshayes, "whether there were 

 anything in the structure of the animal which could 

 explain the singularity, we soon perceived that the 

 upper wall of the branchia] cavity was doubled, 

 and formed a great pouch, the aperture of which 

 was placed backwards, above the origin of the bran- 

 chiae. Plunged in the water, the animal has this 

 pouch constantly filled with the ambient liquid, 

 and, on retiring into its shell and shutting itself up 

 wider its operculum, this bag still remains filled 

 vyith water, and thus furnishes the necessary mate- 

 rials for the function of respiration. Everything 

 leads us to believe that this is the only cause which 

 permits the AmpullarifB, pectinibranchiated aquatic 

 animals, to remain a long time out of the water 

 without perishing, and this explains also how it hap- 

 pens that in certain lakes which are annually dry 

 Ampullariae are always to be found. When the 

 great heats approach and they plunge themselves 

 into the mud or sand, they preserve in their bran- 

 chial sacs the quantity of water necessary .for them 

 during the whole time of drought." 



This, as a writer observes, is one of those beautiful 

 provisions which meet the naturalist everywhere. 

 The tropical torrent and lake may yield to the dry 

 season and burning sun, but the Ampullaria, secure 

 in the possession of his water bag, can afford, like 

 the camel in the desert, to wait till the rains fur- 

 nish a fresh supply, and again fill the parched 

 channel. 



With respect to fossil species of this genus, Mr. 

 G. B. Sowerby states that he is not certain of ttie 

 existence of any ; several, he adds, are mentioned 

 by Lamarck, in the ' Annales du Museum,' among 

 the fossil shells of the environs of Paris ; others, 

 which are thought to be genuine, are fouml in the 

 London clay at Hordwell, and in the mixed stratum 

 between the two fresh-water beds at Headen Hill, 

 in the Isle of Wight. M. Deshayes is of opinion 

 that many fossil species, referred to Natica, ought 

 to find a place in the genus Ampullaria. 



M. Deshayes goes on to state that up to the time 

 when he wrote (1838) there have hardly been found 

 any fossil species of Ampullaria about which there 

 is not some doubt. Those shells which he has re- 

 tained in the genus, from the character of the aper- 

 ture and the small thickness of the shell, are, he 

 says, never met with except in marine formations, 

 and one may always suspect that the animals which 

 produced them were different from those of the 

 Ampullariae properly so called. As these species 

 have the characters of Ampullaiiae, and we have 

 no means of ascertaining the analogy of the ani- 

 mals, we are obliged to have recourse to the cha- 

 racters of the shells and to determine from them 

 alone. But a little time since, he remarks, the be- 

 lief was general that fossil Ampullariae belonged 

 exclusively to the tertiary beds ; but it is now known 

 that this genus occurs through all the " terrains de 

 sediment," for Mr. Sowerby has recorded a fine spe- 

 cies in the transition beds, and M. Deshayes says 

 that he knows many others in the oolitic series, and 

 even in the lower chalk. (Last edition of Lamarck.) 

 The number of fossil species recorded by M. 

 Deshayes in his tables is fourteen (tertiary). In 

 the last edition of Lamarck the number is sixteen. 



The genus occurs in the list of the fossils of 

 Lower Styria given by Professor Sedgwick and Mr. 

 Murchison in their valuable paper ' On the Struc- 

 ture of the Eastern Alps' (' Geol. Trans.,' vol. iii. 

 second series), and in Mr. Mantell's ' Tabular 

 Arrangement of the Organic Remains of the County 

 of Sussex '(ibid.). 

 In the last-mentioned catalogue Ampullariae pa- 



