AND OF THE PHYSICAL SCIENCES. 



147 



dirt that he observed on its plumage." But this assumption of the office of a nurse 

 has been manifested by many birds of the orders Caiitatores, Deglubitores, and Vaga- 

 tores, with regard to helpless individuals, not only of their own, but of other species; 

 insomuch that it would seem to result from the excitement of the parental instinct 

 affected by the solicitations of the destitute orphan. 



In form, as vvell as colour, the Cuckoo is one of the most elegant of our native 

 birds. Its entire length is fourteen inches, the extent of its wings twenty-three, the 

 length of the bill ten-twelfths. The wings and tail are very long, the former straight 

 and pointed, the latter broad and graduated. The plumage is soft and blended. Th« 

 mouth wide, the bill shorter than the head, compressed toward the end, pointed, and 

 somewhat arched. The feet are small, and zygodactyle, that is, having the outer, as 

 well as the inner toe, directed backwards. The bill is greyish-black, at the base 

 orange, the iris also orange, and the bare margins of the eyelids gamboge-yellow, the 

 feet orange, the claws ochre-yellow. The upper parts are bluish-grej, more or less 

 tinged with green ; the quills dusky, the inner webs of the primaries marked with oblong 

 transverse white bands ; the tail greyish-black, glossed with green, the feathers tipped, 

 and along the shafts and inner edges spotted with white. The throat and fore-part 

 of the neck are light ash-grey ; the breast and sides white, transversely barred with 

 brownish-black. The young has the upper parts variegated with light red and dusky. 



GIZZARD OF THE GALLINACEOOS BIRDS. 



We have in two preceding Numbers given a short accoant of the digestive organs 

 of the Gallinaceous and Rapacious Birds. The structure of the stomach in the for- 

 mer, however, requires more particular notice, as it has frequently been misrepre- 

 sented. The accompanying figures are taken from the gizzard of the Black Grouse, 

 Tetrao Tetrix, 



Fig- 



Fig. 1. 



<^-, 





y 



Fig. 1. represents the lower part of the oesophagus, a; the proventriculus, 6, 

 which may be considered as part of the stomach, it being composed of a great 

 number of hollow glandular bodies or crypts, which secrete an abundant clammy 

 duid of a greyish colour. This fluid is carried along with the food into the cavity 

 of the stomach, and is by many supposed to be a solvent of the alimentary mass, ana- 

 logous to the gastric juice in Man and the Mammalia. There is reason, however, for 

 doubting this, and it is probable that the real gastric juice is exhaled by the minute 

 vessels upon the inner surface of the stomach, in the space marked c, of which the 

 cuticular lining is soft. The mass of food, lubricated by the mucous fluid of the oeso- 

 phagus and proventriculus, being deposited in the stomach, is there ground to a pulp 

 by the action of the two lateral or digastric muscles, tf, e, the fibres of which converge 

 toward two tendons, one of which is seen at g. The lower part of the gizzard is fur- 

 nished with a muscle,/', less thick, but still powerful, which, after tiituration is com- 

 pleted, probably aids in propelling the mass towards the intestine, i, while it is pre- 

 vented from escaping into the oesophagus, a, b, by the contraction of the superior 

 muscle, c. The internal coat of the stomach is thick, tough, elastic, and rugous, and 

 has two much thickened portions opposite the muscles, c, d, which perform as it 

 were the office of millstones. There is a muscular dilatation or sac at h, from which 

 the intestine proceeds. The view here given is that of the parts seen from abov**. 

 Fig. 2. shows the same parts viewed from the right side, — a, the oesophagus ; 6, the 

 proventriculus; c, the superior or anterior muscle; d, one of the lateral muscles; f, 

 the inferior muscle; ffy the tendon; A, the sac from which proceeds the intestine, i. 



The birds in which this extremely muscular stomach is found are very numerous. 

 All those belonging to the Gallinaceous order, the Pigeons, most of the Gallatores, 

 and the Swans, Geese, Ducks, and Mergansers, exhibit it in its highest degree of 

 development. A less muscular stomach, although formed on the same plan, is seen 

 m the order Passeres or Insessores of authors, but there it presents various modifica- 

 tions. Many, but not all birds, which have a powerful gizzard, are also furnished with 

 a crop, or dilatation ol the oesophagus, as is the case more especially with the Rasores 

 and Pigeons ; the former of which have extremely large cceca, while in the latter these 

 organs are reduced nearly to the minimum. On the modifications thus prcspnted 

 might be founded an arrangement of birds, which would at least have the merit of 

 placing together those of similar habits. 



ON THE GEOGKAPMICAL DISTRIBUTION OF ANIMALS — NO. V. 



{Continued frowpcige 142.) 



"We now pass on to consider the third division of the subject, the shores and marine 

 productions of South Devon, subjects in a great measure apart from those first discuss- 

 ed; and, although we found it convenient to consider the Fauna of Dartmoor, and 

 the uncultivated districts separately, the productions of those spots are not so distinct 

 or peculiar as those of the shores and sea will be found to be. Divisions of this kind, 

 arbitrary as they are, will nevertheless be found useful, because, as the qualities of the 

 elements and constitution of the climate in each may be expected to differ, it might 

 be also ascertained, that the tribes of creatures inhabiting or frequenting them were 

 more or less classified or brought together by reason of those influences. It is farther 

 convenient for the purpose of comparison with other spots of similar or dissimilar na- 

 tures. "We must, in the first place, say a few words on the Mammalia. 



The chief abode of our Bats is toward the coast, because they principally reside 

 during their daily and diurnal quiescence in the caves and fissures of our limestone 

 rocks, and these occur for the most part toward and on the coast. All our rarer 

 species have been chieSy noticed in caverns on the cnast. Thus Montagu found the 

 two species of Horse-shoe Bat in Kent's Hole at Torbay, and one of these has been 

 captured near Plymouth. The Barbastelle has occurred at Kingsbridge, and the 

 Great Bat 1 have seen several times affecting quarries round Plymouth. The two 

 common sorts seem (perhaps because more plentiful) to resort as freely to old build- 

 ings, hollow trees, &c., as to cavities of rocks ; but, I believe there is no decided pre- 

 ference shown by these animals for natural cavities of the earth; hollow trees, &c., 

 being the appointed substitutes, where and when caves cannot be obtained. It is the 

 same precisely with the Barn Owl, to which hoUuw and wild trees form a natural re- 

 sort, and caves a natural succedaneum ; but both with Bats and the Barn Owl, old 

 buildings, such as barns and sheds, are to be considered in some respects as uimatural 

 habitations, because the creation of animals was anterior not only to the erection of 

 euch buildings, but to the adoption of this island as a residence by our race. It has, 

 however, been most wisely directed that the instinctive faculties of brutes should not 

 be so definite and so limited in their operation, as to preclude all departure from their 

 more peculiar habits and actions, and hence it h.is been found, that the construction 

 and situation of the nests of birds have at times varied remarkably from ordinary rule ; 

 hence birds have been enabled to sustain themselves on novel food, when driven by 

 stress of weather, or other adverse circumstances, to countries which they have never 

 before seen; hence, \^hen detained by weakness, or the allurement of cHmute, and 

 supply of food, from making their accustomed migration, they can support themselves 

 against unaccustomed impressions; and hence, amongst a great variety of other instan- 

 ces not only with birds, but with other kinds of creatures, we are enabled to domesti- 

 cate them, and to cause, by our interference, extraordinary alterations in character and' 

 variations, or rather improvements in instinctive powers. With respect, however, to 

 the adoption of our buildings as places of resort, and situations for nestling by birds 

 and other animals, 1 believe too little has been said by writers, because such irregu- 

 larities have been made to pass current in their mode of expression, and doubtlessly 

 in the mind of many readers, as the natural habits of such species: whereas an useful 

 lesson might be thence drawn, relative to the faculties and mental operations of the 

 beings around \\s. With us the natural nestling places of the Jackdaw are on the sea- 

 cliffs, and rocky eminences in general are its natural abodes wherever found. In 

 defect of these, however. Nature has prompted it to make use of hollow trees and 

 rabbit holes in some instances ; but towers, and ruined buildings, are such faithful imi- 

 tations of its native cliffs, that this bird is diffused very generally through our 

 country. With the Wheatear, old walls and heaps of stones answer the purpose of 

 rocks, both for obtaining food and for nestling. This bird chiefly resides during the 

 breeding time on our coasts, and though it frequents quarries and old walls, these situ- 

 ations are never far removed from the sea-side. At other seasons, it either quits us, 

 or frequents fallows, &c., for food. The natural breeding-places of the Martin, with 

 us, are the cliffs, but owing to similarity of position, and that extraordinary dependence 

 on man observed in this and other species, it usually builds against houses, and frequent.'; 

 our neiofhbourhood. It is remarkable, however, that in the Swift and Swallow so 

 few instances should be on record of their building in other situations besides houses, 

 out-buildings, and churches. I have known a pair of Swallows build a nest in some 

 ivy under a bridge not far from my house, and this too in a loose state, so that it was 

 constantly swinging about with the least current of air, but I am not aware of another 

 instance in this neighbourhood of either of these birds affecting other than the above- 

 named situations ; but, in all likelihood, their natural abodes are like the Martin's and 

 other species known to build similarly, such as the Cliff Swallow and Esculent Swal- 

 low. It would be easy to cite other cases of adopted nesthng-places of the same class, 

 but these are here named because the birds in question seem to belong almost wholly 

 to that portion of South Devon into the productions of which we are now inquiring. 

 The whole character and history of species, and consequently the philosophy of Zoo- 

 logy in general, can only be arrived at by tracing the habits, physical endowments, 

 fee, of animals in each different locality they inhabit; and hence this is one cogent 

 reason for prosecuting the natural history of districts, and comparing and combining 

 th^' same. 



Now, the Otter is an illustration of this. It is usually thought to be a fluviatile 

 animal only ; but in Devonshire it is both fluviatile and marine, quite as many resid- 

 ing on the coast, and fishing to a short distance off the land, as on the banks of our 

 rWers. In the former case, they take possession of small hollows in the rocks, and 

 are yearly hunted in these situations near Plymouth. It might be expected that the 

 Seal would find a place among our Devon animals, but I know of no instance of its 

 capture here, though, from its occurrence in Cornwall, we might reasonably expect 

 that it would be found with us also. 



The Cetaceous Mammalia of our coast deserve more than usual notice in tliis place, 

 because these animals have never been properly examined by British naturalists, 

 and because those which have been seen on our coasts have as yet received very li- 



