of the Island of Cuba. 135 



fish, with the exception of the Lepidosteus, derives directly from 

 the atmosphere the gaseous element ; for, though in different 

 species the bladder communicates with the oesophagus, it is only 

 by a long and narrow duct, which at most might serve for the 

 expulsion of the gas. Matters are different in the Lepidosteus, 

 which receives the atmospheric air in a peculiar organ, opened 

 by means of a muscular glottis at the origin of the oesophagus. 

 But it must be acknowledged that this organ, which according 

 to different authors I had thought cellular, is really vascular, 

 and performs the office of a lung, as I am about to demonstrate. 

 I continue the description of the bladder. It is a thin and 

 transparent bag, which extends throughout the whole length of 

 the abdominal cavity, somewhat bilobed at the two extremities. 

 The longitudinal zone of the centre is simple, but both sides 

 are complicated with an innumerable multitude of tubercles or 

 vessels, which make them appear very much like the lungs of 

 the Crocodile, as also in color, which is sanguineous. There is 

 a tendency to the double lung of the superior animals. The 

 bladder is joined on the superior part to the aorta, and yet more 

 intimately to two venas cavas, which accompany the arte- 

 ry. On opening the bladder, numerous and large tubercles 

 are found on both sides, as well as some smaller ones, and finally 

 a net-work of thin vessels on the internal surface. These latter, 

 which we might call vesicular arteries, branch from the aorta, 

 and entering the bladder, carry the blood from each side to an 

 inferior longitudinal trunk which acts as a common sinus, and 

 from which branch the vesicular veifis, which have the appear- 

 ance of tubercles on the interior of the organ, and which carry the 

 twice oxygenated blood into the venae cavae. The injection 

 which I made into the aorta, assisted by Mr. Francois Cotilla, 

 student of medicine, with a liquid charged with indigo, enabled 

 me to see all the superficial arterioles blue ; the thicker ones, 

 which I have called veins, remaining white. I have seen with 

 a lens, and even with the naked ej T e, the numerous openings 

 with which the aorta is pierced, and I have injected it to that 



