116 



THE EDINBURGH JOURNAL OF NATURAL HISTORY. 



I shall proceed shortly, with the assistance of Mr CoUey, to make out a list of the 

 salt-water shells of this neighbourhood. 



Failing Stars in the jMaur.t.os.-M. Louis Robert, who has long resided 

 in the Mauritius, and devoted his attention to meteorology and astronomy, has ad- 

 dressed to the Institute of Franee an extract from his Journal relative to shooting stars. 

 The coincidence between the appearance of these luminous bodies in an island ot the 

 torrid zone, and those which have been observed at the same time over a great part of 

 Europe, is not without interest. Towards three o'clock in the morning of the 13th 

 November 1832, during calm and somewhat cloudy weather, there were seen from 

 all parts of the heavens, where there were no clouds, and especially towards the 

 zenith, at some degrees to the south, a great variety of shooting stars, which traversed 

 the heavens in all directions. The number was so great that it was impossible to 

 count them. Their courses were not in straight lines, as those of shooting stars 

 generally are, but they described all sorts of curves in the sky. The phenomenon 

 was at its height about four in the morning. A little before the rising of the sun, 

 but fei. of these meteors were to be seen. The mercury of the barometer was at its 

 usual height, and the thermometer of Reaumur was two degrees lower than for some 

 days preceding. ... 



Artificial Formation of Crtstals.—M. Gaudin has lately obtamed micro- 

 scopic crystals of some of the insoluble salts in great perfection, by means of a process 

 which he believes to be applicable to those salts furnishing crystals of all sizes. The 

 method consists in placing certain solutions in an artificial atmosphere; for example, 

 placing under the same bell-glass a capsule containing carbonate of ammonia moistened, 

 and another open glass vessel containing a weak solution of any soluble salt of hme, or 

 baryta, strnntia, lead, &c. ; in a few hours we find on the sides of this vessel crystals 

 of the carbonate of these bases. Sulphate of baryta has been obtained in crystals by 

 placing under the same bell-glass a vessel containing strong hydrochloric acid, and 

 in another open glass vessel, water, sulphate of lime, and carbonate of baryta. The 

 solution of a pure salt of lime gives crystals under the rhomboidal form with its prin- 

 cipal modification, whdst the solution of baryta gives simultaneously crystals of sulphate 

 and carbonate of that base. The author has obtained sulphate of tin from an atmo- 

 sphere of sulphur vapour. Its appearance resembles that of snow. 



Rctiakks on Varieties. 



No two individuals of any species of animal or vegetable are exactly similar. Examine 

 two Elephants, two Chaffinches, two Oysters, two Oaks, two specimens of any one 

 kind of Moss or Lichen ; examine the individuals composing each pair at one time, and 

 placed under apparently similar conditions of existence, and it will be found that dif- 

 ferences exist between them. These differences, however, are of a very unimportant 

 character ; they affect the organization and economy of the being in the most trifling 

 manner. Nature, for some reason, has thought fit that no two of her productions 

 should correspond, not only through the aggregate of species, but also through the 

 aggregate of individuals constituting a species. 



Besides these minor differences between individuals generally, there are others of 

 a higher degree occurring to a great proportion of species in all the tribes and orders 

 of livin"- beings. To these extended degrees of aberration from regular specific cha- 

 racter and appearance, the term " varieties " has been arbitraiily attached by system- 

 .atists ; and in consequence of there being no line of demarcation, natural or artificial, 

 between these and the minor differences first named, contr.arieties of opinion and wa- 

 verings of individual judgment commonly attend inquiries relative to specimens being 

 deserving of the epithet " variety," just as disputes arise whether highly extended 

 varieties may induce suspicions of their title to rank a? species. 



This term " variety " has also been in use in iMineralogy and Geology; but surely 

 its application here must rest on different principles from those which gave it intro- 

 duction into Zoology and Botany ; for, as in the case of animals and plants, the laws 

 of organization and vitality are undoubtedly concerned in the production of varieties, 

 and as the boundaries if species are absolutely fixed by nature, one kind having no 

 alliance with another, so, in the case of inorganic bodies, we witness precisely opposite 

 fads, and a " variety " seems to be an addition to, or reduction from, the characters 

 of the true species, or an assumption of a form of crystallization of the substance, not 

 usual to the species. The number and degrees of these varieties are infinite, and 

 the commixture of species seems to be in a great measure casual, and under no re- 

 strictions. 



Some persons have imag'ned that in the original state of the globe no varieties 

 existed ; but, by arguing the importance of these in the economy of nature, 1 presume 

 a refutation of this notion is effected. Yet I think it quite certain that varieties have 

 increased numerically, the additional instances chiefly occurring among those tribes 

 which, by their organizat'on, allow of variation upon the interposition or presence of 

 some circumstance not usually in operation on the species, but having the power of 

 modifying its structure or aspect, either for a time or during the life of the individuals 

 so affected. It is also highly probabla that these new forms of difference may some- 

 times be permanent, and transmit their peculiarities of structure or appearance to their 

 progeny, with or without the aid of those circumstances which originally induced these 

 varieties. 



These are the two forms of variety mentioned by authors, " accidental" and " per- 

 manent ; " and besides their ordinary occurrence, they may, as I have just said, be 

 produced afresh, or additional instances may be originated. 



In prosecuting our inquiry into the present subject, there is one fact which espe- 

 cially excites attention, namely, the rarity of " varieties" in the upper classes of ani- 

 mals, and their great frequency in the lower departments, and still farther incre:i=e 

 in numbers in the vegetable world. Indeed, with certain interruptions to the ob- 

 servance of this rule, it seems that varieties gradually augment in frequency as we 

 descend in the scale of organization. Farther than this it may be remarked, that 

 amongst the lowest of vegetable productions, no determinate configuration or general 

 aspect of a species is observed, so that there is no standard whereby to judge of the 

 extent of deviation, as can be done in higher classes, but with the exception of certain 

 marks ascertained to be the specific characters, the delations between specimens are 



interminable, all is variety. We must also here notice, by the way, that this unre- 

 strained disposition for variety in the lowest tribes of plants furnishes a proof amongst 

 others that there is a gradual transit from the vegetable to the mineral world, for it 

 happens, as before stated, that the varieties in the species of minerals, or the grades 

 of difference between kinds, are infinite, so that we here find evidence respecting the 

 chain of creation being continued by resemblances between the lowest forms of vege- 

 tation and mineral substances. Some of the zoophytes also which curiously simulate 

 the lowest grades of vegetation in their mode of growth and other circumstances, are 

 likewise perfectly unrestricted in the forms and aspects they assume. 



In taking a view of the whole chain of being, from the most highly to the most 

 simply organized, the interruptions to the rule of increase of varieties are frequent, 

 and in some cases remaikable. Instances occur in most of the families of anim,als and 

 plants, in which no tendency to variation can be traced; whilst, in direct contradiction 

 to our rule, there are animals high in the scale of being suffering numerous variations 

 in the species, and again among plants instances can be adduced, where little or no 

 variety is detected. In the Mammalia varielics are seldom met with. Those gene- 

 rally observed are such as affect only the colour and size of the individual, and these 

 varieties are seldom found to be permanent or capable of being transmitted to future 

 races. There are instai.ces, however, and some of them among British quadrupeds, of 

 varieties in colour, size, and figure, being permanent. Such are the white variety of 

 the Mole, and the three varieties of the Fox. Accidental varieties of colour occur 

 also in the Common Rat, the Domestic Mouse, the Hare, and others. Domestication, 

 however, occasions very considerable variations of structure in quadrupeds, and these 

 capable of being perpetuated. Besides, accidental variations are of very frequent 

 occurrence. But domesticated and cidtivated varieties form a subject quite apart 

 in argument from that under consideration. 



Amon" birds varieties are rather more frequent than among Mammalia, and the 

 slight differences between all individual specimens of each species is a circumstance 

 much more observable here than in the preceding class. I apprehend that permanent 

 varieties seldom occur, but that those usually observed are of the accidental kind, 

 consisting simply in an alteration of the colouring m,atter of the feathers — such are 

 the White Starling, the White Rook, the Cream-coloured Blackbird, the Black Bull- 

 finch, and so forih, — or in deviations from the ordinary number of tail-feathers, or 

 in the addition of a tuft or crest. Domestication causes surprising differences in 

 plumage and structure. 



In the class of reptiles the slight variations observed between individuals are still 

 more considerable than in birds. Varieties occur in respect of size and colour ; and 

 of these an instance is found in our common Lizard, of which three or even more 

 varieties are enumerated. In fishes the differences between individual specimens are 

 very (General and considerable ; and varieties in regard to colour and size, as well of 

 the entire body as of parts, are frequently remarked. There is also one form of va- 

 riety in this class Reserving of separate notice. Some kinds of fish are not sym- 

 metrical in their parts, such, for instance, as the Flounder, which has its eyes placed on 

 the right side of the head. Now, in such cases, varieties occur wherein the lateral 

 arran<Tement of organ? is reversed, the eyes and their contingent structures appearing 

 on the left side. It seems also probable that this sinistral variety is sometimes, or 

 perhaps always, permanent ; but it cannot be a matter of much moment to determine 

 whether a variety is constantly being reproduced lineally from the original stock, or 

 first parents or originators of that variety, or whether it is continually being produced 

 as an accidental form of variation from parents of the ordinary configuration and 

 appearance. 



In examining the class of Molluscous animals, we find the differences between 

 specimens of still greater degree. Varieties are likewise numerous, and are carried 

 to a greater extent than in the classes we have yet viewed. Colour and size in par- 

 ticular are subjects of variation ; so are relative proportion and arrangement of parts. 

 These all form accidental or permanent varieties, and I believe that sometimes the 

 same form of variation occurs both accidentally and permanently. In the case of Uni- 

 valve shells, reversed specimens are sometimes noticed, such as the sinistral variety of 

 Hdix Pomatia. But, besides these, there are instances of varieties in shells, where 

 the individual must suffer much more considerable alteration or deviation from the 

 ordinary growth of the species. Such are the varieties in the genus Chiton having 

 seven or even six valves, eight being the regular number. So also we frequently see 

 varieties in spiral shells, where one or more whorls are superadded to the usual num- 

 ber. Lister records a variety of Lymnsa stagnalis having the tentacula or feelers 

 branched ; and I have seen a specimen of Helix iimhdicafa, collected by Mr T. CoUoy 

 of Plymouth, in which the last whorl, instead of completing its gyration, protruded 

 diagonally from the shell, forming a projection nearly a quarter of an inch long. By 

 such circumstances it appears that great latitude of variation obtains among the ani- 

 mals of this class, and that these varieties are by no means confined to colour and 

 size, instances of which abound in all collections of shells, but extend likewise to dif- 

 ferences affecting more decidedly the structure and anatomical arrangement of the 

 animal. 



In the remaining tribes of animals the differences between specimens belonging to 

 the same kind are very considerable, insomuch that in the m.ajority of species it is 

 necessary to disregard external aspect and general appearance in distinguishing species, 

 and to concentrate the attention on those parts liiely to afford a clue to correct and 

 final opinion. Moreover, we may observe that these differences are so great as to be 

 equivalent to varieties in higher classes, and they seem to merge by insensible degrees 

 into positive varieties amongst themselves. In the Asteriadae we notice an interest- 

 ing form of variety, consisting of the reduction from the ordinary number of arms, or 

 of additional developments of the same. This is seen in two or more of our native 

 AsteriEB. — (To be continued,) 



Edineuroh: Published for the Proprietor, at the Office, No. 13, Hill Street. 

 London: Smith, Elder, and Co., 65. CornhiU. Glasgow and the West of 

 Scotland: John Smith and Son; and John Macleod. Dublin: George 

 Young. Paris: J. B. Balliere, Rue do I'Ecole de Meilocine, No. 13 bis. 



TIIE KDINBUR.GH PillNTING COJIPA.NT. 



