214 



MUSEUM OF ANIMATED NATURE. 



[NERlTIDiE. 



that of the A«trolabe has rendered them common. 

 The place probably mo«t frequentec' by them is, 

 according to these zoologists, Port Wesfem in 

 Bais't Siiait. They cover the sandy beaches of 

 thi» vast tract. Each tide carries these mollusks to 

 the shore, where they live hi^h and dry for some 

 hours, and endeavour to withdraw themselves trom 

 the heat of the sun by hiding under the (uci. 

 Under such shelter they congregate so numerously 

 that seventy-six were found under one of these 



The' Phaiianellffi, observe the same zoologists, are 

 always smooth. This polish, and, still more, their 

 contmiial movements, prevent them from being 

 covered with Serpulae, Flustrae, and other parasites 

 which encrust sluggish shells. Their agitation, 

 however, makes it difficult for them to preserve the 

 contour of their aperture perfect, lor it is very frail. 

 In millions of individuals MM. Quoy and Gaimard 

 always found the lip trenchant, never thick or with 

 a border. 



The species appeared to them very difficult to 

 characterise, botn with re(^ard to the animal and 

 the shell. The last especially presents so much 

 diversity of colour, and sometimes of form, that one 

 may be deceived, and advance simple varieties to 

 the rank of species. MM. Quoy and Gaimard saw 

 some of these shells, which were brown and greenish 

 during life, become red alter death by the solar 

 action, &c. 



The most common tint of these mollusks is stated 

 by them to be brown dotted with greenish. This 

 colour is proper to those whose shells are nearly of 

 a similar hue ; whilst those which approach white or 

 are speckled with red have the animal of a grass- 

 green. 



These are lively active animals, and voracious 

 withal, for they were taken in nets baited with 

 flesh let down into the sea. Their foot, endowed 

 with great mobility, is elongated like a proboscis : 

 its great peculiarity is its faculty of moving in two 

 portions as it were,— that is to say, each of its 

 sides advances separately and successively ; and a 

 longitudinal gutter may be perceived on its lower 

 surface. 



On the coasts of New Holland, the Phasianellse 

 found at King George's Sound are larger and less 

 numerous than at Port Western. They are few in 

 number on the coasts of Van Diemen's Land. The 

 operculum is always calcareous. 



2687— The Bulimoid Phasianella. 

 {PhasianeUa bulimoides). The shell of this species 

 is oblong-conical, smooth, pale yellow, transversely 

 banded ; the bands frequent and diversely variegated 

 and spotted ; spire acute at the apex. 



The animals are generally of a tine green nearly 

 throughout. One will have more white dots on the 

 foot, and another a violet or reddish spot on the 

 lateral fringes of the foot; a third will have this 

 organ yellowish and slightly fringed upon the 

 borders. In all the tentacles are slender and long, 

 the ocular peduncles stout and button-shaped, the 

 palmettes laciniated. The muzzle, which is elon- 

 gated a little in the form of a proboscis not retrac- 

 tile, can also modify itself into the shape of a 

 rounded scutcheon (^cusson). The fringes of the 

 sides of the feet are very finely laciniated, and 

 sometimes present brown ramifications of vessels; 

 they carry three greenish filaments on each side. 



The operculum is oval, calcareous, slightly 

 convex, white, and covered for a portion of its 

 contour by a fleshy lamina of the foot which sup- 

 ports it. 



The Phasianella bulimoides is very common at 

 Port Western, and larger at King George's Sound. 

 MM. Quoy and Gaimard observe, that Lamarck 

 indicates it as coming from New Zealand ; this, they 

 remark, is possible, but they never found any traces 

 of Phasianellee there. 



Referring to Fig. 2687, a represents the animal 

 and shell seen from below ; b, the same seen from 

 above ; c, the shell ; d, the operculum. 



2688. — The Roseate Thebitella 

 (TurriteUa rosea). In the genus Turritella, to 

 which different positions have been assigned by 

 various naturalists, the shell is turriculated, pointed, 

 and generally striated in the longitudinal direction 

 of the whorls of the spire, which are numerous : the 

 aperture is rounded and entire. 



The Roseate Turritella has the whorls almost 

 smooth and is of a roseate tint, which changes to 

 brownish or dull reddish after the death of the 

 mollusk. The animal has the muzzle elongated 

 into a proboscis ; the tentacles are moderately long 

 and slender, carrying sessile eyes very near their 

 base ; the colour is brown dotted with black ; the 

 mantle has its margin fringed and sprinkled with 

 whitish lunulate marks. The operculum is delicate, 

 round, and multispiral. 



This species was found in great numbers by MM. 

 Quoy and Gaimard in the Bight of the Astrolabe, 



New Zealand, at the depth of several fathoms. 

 They are timid animals, seldom protruding from 

 their shells. Length neariy three inches : a repre- 

 sents the shell and animal ; b, the operculum. 



2089. — ^Thi Awl-shaped Tl-rbiteij.a 



(Turritella terebra). This species is found in the 

 African and Indian Seas: the whorls are sulcated ; 

 the colour reddish. 



Both living and fossil species of Turritella are 

 very numerous : of the former M. Deshayes found 

 twenty-four species, and of the latter, in tertiary 

 strata, forty-five species. 



Turritella, however, occurs in ancient formations, 

 both anterior and posterior to the chalk. See 

 Dr. Fitton's ' Stiatigraphical Table." In this five 

 species are recorded, ranging from the upper green- 

 sand to the Oxford oolite inclusive. Four species 

 are described by Mr. Murchison as occurring in the 

 middle and lower beds of the old red sandstone 

 (Silurian rocks) and the lower Ludlow rock. 



2690. — The Common Faue Wentleteap 



(Scalaria communis). The situation of the genus 

 Scalaria has been varied by different naturalists 

 according to their respective views: Cuvier places 

 it near Turritella. The shell is subturriculate, with 

 the whorls more or less close, and furnished with 

 elevated longitudinal ribs. The operculum is horny. 

 At least eighty distinct species are known ; they are 

 deep-sea shells, ranging from seven to thirteen 

 fathoms in sandy mud. A section commonly called 

 True Wentletraps are found in the seas of warm 

 climates, but many of the False Wentletraps, as the 

 other section is called, occur in the European seas 

 and on our own coast. Of these the Scalaria com- 

 munis is an example. The ribs in this species are 

 rather thick, smooth, and suboblique. The general 

 tint is whitish or pale fulvous, but a large variety 

 occurs of a rosy violaceous tinge, with purple-spotted 

 ribs : a represents the front view of the shell ; b, the 

 back view ; c, the operculum ; d, the animal with 

 its shell. 



269L — The Royal Staircase Wentleteap 



(Scalaria pretiosa). Aciona Scalaris, Leach ; La 

 vraie Scafata. This beautiful and highly valuable 

 shell is a native of the Indian and Chinese seas. It 

 is conical in general form, umbilicated, and contorted 

 into a loose spire. The ribs are bold and apart. The 

 general tint is pale yellow, with the ribs white. The 

 term pretiosa was given to this shell by Lamarck from 

 the great price which a good specimen would bring 

 in the market, especially when it exceeded two 

 inches in height. Such a specimen, we are assured, 

 " has been sold in former days for 2400 livres, or 

 100 louis ! But those times are gone by ; the shell 

 is no longer rare, and good specimens only fetch 

 shillings where they once brought pounds. A very 

 fine example, however, still commands a consider- 

 able sum. That in Mr. Bullock's museum, supposed 

 to be the largest known, brought 27/. at his sale, 

 and was in 1815 estimated at double that value." 

 a represents a front view, showing the mouth ; b, the 

 back view ; c, a view to show the whorls are dis- 

 connected. 



We may now proceed to a group of shells con- 

 sisting of the genera Nerita, Navicella, and Natica, 

 which, though they cannot, as an eminent naturalist 

 remarks, be said strictly to belong to the Turbinidae, 

 are yet so far analogous to the forms which compose 

 that family, that we may here bring them under 

 notice. They form part of the family NeritidaB of 

 Mr. Gray. , 



With respect to the genus Nerita of Linnaeus, 

 Adanson appears to have been the first who made 

 known the animal inhabiting the shell, and Cuvier 

 afterwards gave an outline of it in his ' Anatomic 

 Compar6e.' In the ' Zoology of the Uranie ' M. de 

 Blainville added to our information ; and MM. Quoy 

 and Gaimard, who brought home numerous speci- 

 mens, give some interesting details in the ' Zoology 

 of the Astrolabe.' 



They observe that the Nerifs are marine or fresh- 

 water animals, a modification of habit which they 

 think sufficient for establishing a simple division 

 between these mollusks, which Lamarck erroneously 

 in their opinion separated into two genera — Nerita 

 and Nentina; for their organization is entirely 

 similar. Thus the Neritae, with a comparatively 

 thick shell, which is very rarely furnished with an 

 epidermis, are always found in the sea ; and the 

 Neritinae of Lamarck, whose shell is more delicate 

 and almost constantly covered with an epidermis, 

 are always inhabitants of fresh water : a single in- 

 stance of one of these Neritinse having wandered into 

 the sea, they may, they say, perhaps have had to cite. 

 The Nerits have a particular and distinctive appear- 

 ance : they pass a part of their life out of the water 

 without ever removing to a distance from it. Those 

 which haunt streams or marshes may adhere to the 

 leaves of trees, but without going on land. Those 

 which are found on land are carried there by Paguri 



(Hermit crabs), or by some accident. Marine Nerits 

 are also seen at the mouth of rivers ; and MM. 

 Quoy and Gaimard remark that these are transi- 

 tions which nearly all the mollusks undergo with- 

 out suffering much. 



MM. Quoy and Gaimard state that they were 

 sometimes astonished to see these animals upon 

 the black rocks, exposed to all the action of an equa- 

 torial sun without appearing to be afl'ected by it 

 They owe this faculty of enduring heat to the ci> 

 cumstance of having previously taken in some drops 

 of water which sufficiently refresh their branchiae. 

 This store, or what is left of it, they discharge when 

 they are lifted from the rock. 



The Nerits are very widely spread in warm cli- 

 mates. They are gregarious, and many species are 

 found grouped on the same rock. Some love shel- 

 tered nooks, others are exposed to the fury of the 

 waves : and, among those which haunt fresh waters, 

 some live in the deeps in the midst of the strongest 

 currents ; others, on the contrary, keep themselves 

 in the slime of marshes. In their sufficiently agile 

 movements their lips are constantly observed in 

 motion. 



The animal has a large head, a little notched in 

 front, with two rounded lobes on the sides. The 

 aperture of the mouth, which is subjacent to this 

 sort of hood, is wide and plicated. The tentacles 

 are always very long, pointed, and soft, carrying the 

 eyes at their base upon a pedicle. The foot is oval, 

 narrowed, a little pointed behind, wide in front, 

 with a marginal furrow, and sometimes a depression, 

 which gives it the appearance of being slightly 

 lobated. 



The edges of the mantle are fringed, so as to cor- 

 respond with the internal furrows of the shell. "There 

 is no siphon. "The pulmonary cavity is proportion- 

 ally very large; a single, long, triangular, and 

 pointed gill traverses it from left to right. It is free 

 at its extremity. Its lamellae appeared double to 

 MM. Quoy and Gaimard. The heart is simple, 



E laced backwards and to the left ; its ventricle em- 

 races the end of the intestinal loop, which has the 

 appearance of traversing it. 



2692.— The Polished Neefta 

 (Nerita polita). "This species is distributed through 

 nearly all the hotter seas. The shell is heavy, thick, 

 and polished, and very finely striated longitudinally : 

 the spire is very retuse ; the lip toothed. It is mar- 

 bled with blended tints, and often adorned with 

 three red transverse bands ; the animal is yellowish 

 with dusky tentacles. 



2693.— The St. Ascension Nerita 



(Nerita Ascensionis). The shell of this species is 

 solid, transversely furrowed, and ribbed, with the lip 

 toothed ; the aperture is white ; the general colour 

 of the shell yellowish grey, with brown marks upon 

 the parts in relief. The foot of the mollusk is yellow 

 below ; striated and thickly dotted with brown on 

 the sides, as is also the head above ; the tentacles 

 are streaked with black ; the neck is violet. The 

 operculum is reddish brown and granulated ; a little 

 spur projects from its angle, a represents the shell 

 and animal ; b, the operculum. 



2694.— The Neritina 



(Neritina pulligera). Nerita pulligera. The 

 shell of this fresh-water mollusk is ovate and 

 slightly striated ; the outer lip is dilated and thin, 

 the inner lip toothed. The general colour is chest- 

 nut brown ; the inner lip yellowish ; the outer white 

 within. The operculum is green with black trans- 

 verse bands. "This species was found by MM. Quoy 

 and Gaimard in the island of Guam, and also at 

 Vanikoro. They frequently observed on the trees 

 dead shells of this species, with the spire always 

 corroded, and inquire whether they had been brought 

 there, or whether the animals had died after having 

 ascended the trees. They further state as a remark- 

 able circumstance, that in numerous individuals 

 they found in the liver a small knot of parasitic 

 worms, some of which were an inch and a half or 

 more in length ; they were pointed at both ends 

 like lumbrici. At Fig. 2694, a represents the shell 

 and animal ; b, the operculum. 



2695. — The Elliptical Navicella 



(Navicella elliptica). The genus Navicella, except 

 in the disposition of the operculum and in the mus- 

 cular attachment of the animal to the shell, 

 closely resembles Nerita. The operculum is 

 very singular ; it is placed above the foot ; its 

 form is somewhat quadrilateral, and is adherent 

 throughout the extent of its lower surface ; in its 

 natural situation it seems as if contained in a sortof 

 pouch between the foot and viscera, so that it 

 cannot, as M. de Blainville observes, really serve 

 the ordinary purposes of an operculum. 



The shell is oval and elliptical, with a slight 

 greenish brown epidermis, smooth, shininc, and 

 spotted with white and blue. 



