136 Observations on different points of the Natwal History, dec. 



effect after having separated the bladder. I have not injected 

 the longitudinal sinus ; but I hope these experiments will be 

 repeated and completed in the United States, and also extended 

 to other species of fish. 



Before demonstrating anatomically that some sort of pul- 

 monary respiration existed in the Lepidosteus, the following 

 facts might have led one to expect it. The animal, when placed 

 in a basin filled with water, maintained itself there all day with- 

 out movement. The branchial respiration was effected by a 

 constant motion of the lower jaw and the opercular bones ; the 

 motion of the jaws being hardly visible, that of the opercula 

 more so. I have counted forty acts of respiration per minute. 

 Every five to eight minutes he would come to the surface to 

 swallow a mouthful of air, returning downwards immediately. 

 One second after, half a dozen air-bubbles, some quite large, 

 escaped by the opening of the branchiae. The air remains in 

 the bladder one second, sometimes one and a half, and this 

 time is probably sufficient for the absorption, digestion, and 

 expulsion of the inspired air. Besides, it is certain that the 

 animal not attempting to swim, the bladder was not used in 

 augmenting or in diminishing the density of the body, as most 

 fish do, in order to ascend and descend in water. 



I have spoken in my "Memorias" of transverse filaments, 

 which I supposed to be muscular, and serving to compress 

 the bladder in the act of expiration. I was mistaken, for I had 

 only examined parts of organs separated from the body of the 

 animal. These pretended filaments are merely canals which 

 connect two bodies (which I took for deposits of fat) with the 

 duct running along the vertebral column, and where the granu- 

 lation of the veins accumulates. These bodies are white, flat, 

 prolonged in the form of a half circle, and containing a milky 

 liquid. Are these the soft roe or ovaries, or are they part of 

 the urinary apparatus ? The fact is, that these canals lose 

 themselves under the peritoneum. The kidneys are more 

 voluminous at their posterior termination, and the urine issues 



