164 | Miscellanies. 
‘none is so fierce that dare stir him up.” But all vitality, all mus- 
cular energy, depends on the act and effects of respiration; and how 
are these habits of the crocodile to be reconciled with this law? On 
land, when breathing the atmosphere at full, he is sluggish and fear- 
ful; it is only when immersed in water, and when respiration is liable 
to be impeded, that he acquires strength, activity, and courage. 
There is here an exception to the law, but it is only in appearance; 
and it is curious to remark how simply nature in this case enlarges the 
respiratory organ and function, and gives the aquatic creature its cor- 
responding power, without deviating in any thing from the one model 
of organization. By means of two canals which take their origin inthe 
cloacum, and which open into the cavity of the peritoneum, water is 
conveyed within the abdomen to act upon the blood in its vessels; 
and through the abdominal vessels thus called upon to aid the lungs ia 
oxygenating the blood, the additional vigor to the muscular system 
is imparted. The crocodile has an abdominal sternum independent 
ly of its pectoral sternum: each sternum and its muscles regulate the 
effects of their proper and respective respiration. When the animal 
is on land, it is the thoyax and its sternum which are only in action; 
when in the water, the abdomen and its sternal apparatus are like- 
wise called into play. Isidore Geoffroy Saint-Hilaire and Joseph 
Martin were the discoverers of the canals which open into the pert 
toneum ; a discovery of great interest, as previously to it the habits 
of the crocodile were inexplicable.—WMag. of Nat. Hist. Sept. 1930, 
6. Are the songs of birds innate or acquired ?—This question has 
occasioned some controversy among the contributors to Loudon’s val 
uable Magazine of Natural History. One writer (R. Sweet, Pomont 
Place) maintains that blackbirds or thrushes, brought up in @ citys 
will have no variety in their notes, and will only imitate the tones 
people who whistle to them, or the discordant noises of the streets 
A nightingale, caught when young, and which he had kept for thre? 
years, only sang two or three notes, It was turned out in the sv” 
mer, migrated in autumn with other birds, but returned in the springs 
and was recognized by its imperfect notes. Another bird (Saxicolt 
Rubetra, or Whinchat) bred from the nest, turned out to be 2 Ve 
fine singing bird, but its notes were all acquired by mocking other 
birds, and had scarcely any thing in them of the natural sung of 
species. Other birds, which had acquired their own wild notes whe 
taken, learned also to imitate the cage birds around them. , 
