14 BULLETIN OF THE 



face 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," he adds, "remains in the blad- 

 der 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 w T as not used in augmenting or diminishing the density of the 

 body, as most fish do, in order to ascend and descend in water/' Poey 

 further strengthened his opinion that " some sort of pulmonary respira- 

 tion existed in the Lepidosteus " by dissections and injections of the 

 aorta, which showed the great vascularity of the bladder (pp. 134-13G). 



Louis Agassiz ('57), in exhibiting before the Boston Society of Natu- 

 ral History some young living gar-pikes, called attention to the fact that 

 this fish is " remarkable for the large quantity of air which escapes from 

 its mouth. The source of this Prof. Agassiz had not been able satis- 

 factorily to determine. At certain times it approaches the surface of 

 the water, and seems to take in air, but he could not think that so 

 large a quantity as is seen adhering in the form of bubbles to the sides 

 of the gills could have been swallowed, nor could he suppose that it 

 could be secreted from the gills themselves." 



More recently Wilder ('76 and '77) also has studied the young of this 

 fish. He says ('7G, pp. 151-153): "Very often these young indi- 

 viduals of L. osseus, and more frequently the adults of the smaller 

 species (L. platystomus), would protrude the snouts from the water in 

 the respiratory act ; but the length of the jaws made it impossible to 

 determine whether this was intentional, and for the purpose of inhaling 

 as well as of exhaling the air." He inclined to the ojjinion that air is 

 taken in as well as given out, because the fishes uniformly approached 

 the surface, whereas, if exhalation were alone sought, that " could be as 

 well accomplished at any depth." As the result of some experiments in 

 restraining the motions of Amia, he says : " There seems no doubt that 

 with Amia there is a true inspiration as well as expiration of the air. 

 The same may be considered probable, though not yet proved, with 

 Lepidosteus" 



So far as I know, these are the only published accounts of this pe- 

 culiar habit in the case of Lepidosteus. While Agassiz maintained a 

 conservative attitude regarding the question of the source and nature of 

 the bubbles, Poey and Wilder expressed the conviction that it was air 

 w r hich had served the ordinary purposes of respiration, and both of 

 them supported their belief with arguments. 



