M LIMAX 



peelais.rfvoir lpirmKri<mr." Those among them, ho add*, which 

 ban DO apparent shell formed, according to Linnieua, the genus Lima*, 

 which CuTHir ubdivide into the group* of the Limaeea, or Slug* 

 property called (, Linn.) ; the Testacelle. (Tai^dla, Urn.) ; 

 and the Parmaeelles (ParmmcttU, CUT.). In the last edition of the 

 Bin* Animal* (1830), be adds under XMMUC the subdivisions din- 

 sswiiitiH by D Ferussae, namely, jlrio* and l>ywW. 



IB both edition, he describes the Limaoe* proprement dita* M 

 Urine an elongated body, and for mantle a fleshy compact due, 

 which occupies the anterior put of the body alone, and coven the 

 pulmonary oarity only. Thi* due contain*, be adds, in many species, 

 a (mall oblong and flat hell, or at leait a calcareous accretion in lieu 

 of it The orifice of respiration is on the right side, towards the front, 

 and the anna U pierced at it* posterior border. The four tentacles 

 are pat forth and withdrawn by unrolling themselves (en ae deroulant) 

 like the fingers of gloves, and the head itself can be withdrawn in 

 part under the duo of the mantle. The organs of generation open 

 under the right upper UnUclc. There ii but one jaw (upper), in the 

 form of a dentilated crescent, which serves them to gnaw with much 

 voracity the herbs and fruits to which they do so much damage. 

 Their stomach is elongated, simple, and membranous. 



Lamarck ('Histoire Naturelle des Animaux sans Vertebras,' torn, 

 vi. part u. 1822) thus defines his Limaciens : Branchitc creeping 

 (rampantes), under the form of a vascular net upon the wall (paroi) 

 of a particular cavity, the aperture of which is a hole which the 

 animal contract* or dilates at its pleasure. They respire the free 

 air only. 



The same zoologist remarks that the Limacians constitute a natural 

 family and a very remarkable one, inasmuch as the animals which 

 compose it are the only ones among the Gastropoda whose respiratory 

 organ, which is truly branchial, breathes nothing but free air, and he 

 thence names them Pneumobranches. These molluscs, he continues, 



or nearly naked. Their body is elongated, creeping upon 

 a ventral disc which is not separated from it, and bordered on the 

 aides by a mantle which U most frequently very narrow. Originally 

 from the waters (originaires des eaux), they live habitually in their 

 neighbourhood ; but some inhabit, nevertheless, places which are at a 

 distance from the water, but nearly always in cool and humid locali- 

 ties. They have accustomed themselves (Us se sont accoutumes) to 

 breathe air with their branchial; so that this habit ban become a 

 necessity to them. Here it is, for the first time, as regards the 

 oBisini. that the free air is the fluid breathed. This fluid penetrates 

 by a bole, and without either trachea or bronchia; into n particular 

 cavity which is not divided into many partitions (loges) or cellules, 

 bat on the walls of which little lace-like vessels or a vascular net- 

 work (des eordonneU ou des Ucis de vaisseanx) creep in divers forma 

 and receive the influence of the respiration. A similar or analogous 

 cavity is found in a great number of the Trochelipods ; but in those 

 which respire sir only, the influence of this fluid, being very superior 

 to that of water, requires in the organ presented to it only a very 

 mall surface. Thus the vascular lace-like work (cordonnets vascu- 

 lures) which creeps over the walls of the cavity, and which in that 

 respect resembles the same part* in the Lunarian*, projects very little; 

 whilst So those which respire water only the cavity offers very pro- 

 jecting and vascular parts (uch as pectinated lamina) of different 

 ties) to the inflames of the fluid respired. The branchial cavities of 

 which we an speaking, even that which is adapted for breathing air 

 only, cannot be reasonably confounded with a lung, which is a respira- 

 tory organ of a particular fashion, adapted to organisations of a 

 superior order, an organ which is essentially cellular, and into which 

 the fluid respired is introduced at least by an internal trachea, and 

 Us* by bronchia) besides. This modification, then, of the respiratory 

 organ has peculiar characters which branchial or gills, whatever be 

 air form and situation, never offer. If, in order to determine the 

 name or the kind (eepeco) of a respiratory organ, that organ is consi- 

 dered only with reference to the fluid respired, then all animals which 

 respire free air may be said to pesetas a lung ; but if, in order to 

 facilitate the stody of the different modifications of organs which 

 *sr for respiration, and in order to seize the means which nature 

 has employed to effect the progressive composition of the animal 

 nfgsulsalluli u well as Its perfection, one considers the characters 

 proper to each sort of respiratory organ, it will then be evident that 

 OB"** ant Jay BUM liatUUaU animal respires by means of a 

 I*** lHfcnA many among them respire the free air. Besides, inde- 

 pepdeotly of the particular and well-known structure of every luug, 

 the air new ; iisUrtu except by the mouth of the animal, whilst in 

 every respiratory organ dUtioct from a lung the fluid respired, what- 

 ever H be, is always Introfcmd by another passage. To confound 

 objects so diflerent, each of which is appropriated to the degree of 

 organisation to which it belongs, and can only exist in an organisation 

 of that degree. Is, in our opinion, to render the knowledge of the 

 order of aatare in her MUllJutiuui impossible. In fact, in the course 

 of UM animal kingdom, such a function could not be executed except 

 by an organ or system of organs differently modified, because it must 

 be in relation with the utate of organisation of which it forms a part. 



To return, continue Lamarck, to the particular object before us, 

 I will sav that braMUav hho.^L they present themselves under a 

 moltfeode oT IbniM art diftmtit situation*, never resemble, notwith- 



UMAX. 438 



standing, a lung. This respiratory organ, then, U peculiar ; and we 

 know that it has the power of habituating itself to respire air. In 

 fact many Crustaceans which live nearly constantly on land respire 

 there this last fluid only with their branchiae. If the Colitnacds, aa 

 well as the Liinneans, have a branchial cavity similar to that of the 

 Limacians, and breathe the free air only, this cavity is also the same 

 as that of the Melanians and other Trachelipods which breathe water 

 only. But in the first the respiratory organ presents a small surface 

 only to the fluid respired ; whilst in the second the organ in question 

 offers a much larger extent of surface. In each case these organs 

 are always branchial, but adapted to the power of the influence of 

 the fluid respired, and situated in analogous cavities. 



Thus far Lamarck, who concludes by comprehending under big 

 Limacians the following five genera : Onchidinm, Parmacdla, Lima, 

 Teitacclla, and Vitritta. 



The second section of the Limacmeans of M. De Blainville, or 

 those which have the anterior border of the mantle enlarged into a 

 species of buckler, the shell being null or nearly membranous, consist 

 of the genera Vitrina, or Ifelicolimax, TestacMa, Parmacetta, Lima- 

 cella, Limax, and Onchitlium [LiM ACTXEA], With regard to the marine 

 species, which Cuvier has approximated to these, M. De Blaiuville 

 observes that they constitute his genus Peronia in his order of 

 Cyclobranchians. [NDDIBRANCIIIATA.] 



M. Rang arranges the Limaces of Fdrussac (Limaciens of Lamarck, 

 Limacinda of De Blainville, Nudilimacea of Latreille) aa the first 

 family of the Pulmouea Inoperculds of De Fdrussac (Pulmobrauches 

 of De Blainville), and makes it consist of the genera Onchit, For. ; 

 Oncbidie, Cuv. ; Peronia, De Blanv. ; Onchidium, Buchanan ; Keren*- 

 cclta, De Blanv. ; Vayinuliu, De Fdr. ; having a general cuirass. 



The genera Limacclla, Blainv. ; Limax, Lam. (including Arion, 

 For.) ; Parmatella, Cuv. ; which have a partial cuirass : and 



The genus TettaceUa (including the Plectrophore) of Fdrussac, which 

 ia without any cuirass. 



M. Deshayea makes the following remarks on Lamarck's classification 

 of thia group of Molltuca :" We have already oenaured in the method 

 of Lamarck the separation of the Gastropoda and the Trachelipods a 

 separation artificial and useless, especially aa regards the grand series 

 of molluscs, where thia division ia the less tolerable, because there it 

 ia that the passage of the Gastropoda, properly so called, and of the 

 Trachelipods is effected in the most imperceptible manner and by 

 means of a curious series of modifications. Cuvier, who, in his 

 memoir on the Limacei and Jlclicct, has justly advanced the proposi- 

 tion that there scarcely exist any zoological characters proper for the 

 distinction of these two genera, could not coincide in the opinion of 

 Lamarck, and in this he was wisely imitated by the greatest number 

 of zoologists. M. de Fdrussac collected into two orders all the air- 

 breathing molluscs, according as they were or were not provided with 

 an operculum. Those which are operculated are few, and consist of 

 two genera only, which we find among the Trachelipods of Lamarck. 

 Those which are not operculated comprise a considerable number of 

 genera grouped in families. The first ia that of the Limaces, corres- 

 ponding exactly enough with the family of Limacians of Lamarck. 

 It comprehends however twelve genera, whilst that of Lamarck only 

 contains five ; but when we come to examine attentively these different 

 genera admitted by M. de Fdrussac, we soon perceive that many are 

 too uncertain to bo definitely adopted. M. De Blainville himself has 

 rejected many of the genera of this family which he had at first 

 adopted; and in his ' Treatise on Malacology' he has reduced them 

 to five. M. Cuvier, in the last edition of the ' Regne Animal/ has not 

 adopted more than the genus Vaginultu, to which M. De Blainville has 

 given the name of Peronia, which occasions a sad confusion in nomen- 

 clature. It will suffice then to add the genus Vaginal tu to the family 

 of Limaciatu of Lamarck, to render it as complete aa the most positive 

 observations require." 



Dr. J. E. Gray is of opinion that at present only a few genera, as 

 Arion and Jfelicarion, Fdr., Nanina, Gray, and Sltnoput, Guilding, can 

 be referred with certainty to the Arionida;, though he thinks it very 

 probable that, when the animals of other sheila are known, many of 

 them may be found to belong to that family. In this state of our 

 information we shall confine ourselves in this article to those forms of 

 the naked truly terrestrial Limaculir., which are for the moat part 

 popularly known under the name of Slugs, and shall notice the genera 

 with external shells under their respective titles, though we quite agree 

 in the principle of the general similarity of the zoological characters 

 of the Limacei and Ildicei, and the almost imperceptible gradation of 

 form among them. [ I li:un n.v.] 



VayinHltu (Fdrussac). Animal oblong, elongated, often very slender 

 in its state of extension, convex above ; a cuirass covering the whole 

 of the body, extending beyond it, and forming in front a sort of hood, 

 wherein the head can be withdrawn ; mouth armed with an upper 

 jaw ; four contractile tentacles, the two upper ones long and oculiferous, 

 the anterior short, and, as it were, palmated or bifurcated at their 

 extremity ; the foot oblong, elongated ; the respiratory cavity towards 

 the middle of the body having its orifice behind, at the extremity of 

 a long canal, and separated from the anus by a membrane only : organs 

 of generation very distinct on the right, the male organ being near the 

 small tentacle, and the orifice for the egga towards the middle ; no 

 terminal mucous pore. 



