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THE AMERICAN NATURALIST [Vol. XL 



is sufficient for the purification of the blood. This fact shows 

 the importance of the cutaneous respiration and the insufficiency 

 of the pulmonary." 



Food. — Concerning their natural food little is known beyond 

 the fact that dissections of the alimentary tract reveal the presence 

 of small crustaceans, insect larvae, and occasionally a small fish. 

 Harlan ('35) and James ('23) both record having found earth- 

 worms in the alimentary tract. Kneeland ('58) says: "They 

 seize living worms eagerly and suck them down, if small, with 

 a single sudden swallow; if the worm be large, it is swallowed 

 by repeated suctions, the teeth preventing its escape; the act 

 of suction may be seen by the movements of the impurities in 

 the water, as it is drawn in and afterwards expelled. They often 

 miss the worm; sometimes it may be too far off, but at others 

 so close to them that it seems that their vision must be imperfect. 

 They will not eat a dead worm unless they have been kept with- 

 out food for a considerable time." 



A very curious performance was witnessed by Kneeland and 

 reported by the secretary of the Boston Society of Natural His- 

 tory as follows: "A number of Necturi had been without food 

 for five months when four living minnows were placed in the 

 aquarium, three of the four minnows were swallowed before 

 the expiration of fifteen minutes, and among them the largest. 

 After they had swallowed them, they seemed very uneasy, moving 

 the bones of the head and jaws, and contorting their bodies in 

 various ways, as if they did not feel quite easy in their stomachs; 

 however they at last became quiet, but at the end of twenty hours 

 they became uncommonly active, and the three fish were regurgi- 

 tated with the scales off, the eyes out, and the entrails of the 

 smallest gone; they were perfectly white, and looked like ghosts 

 of fish. It was either diet to gross for their delicate and weak- 

 ened stomachs, or else not sufficiently comminuted for the action 

 of their gastric juice." Gamier says that they eat small living 

 fish and crayfish by preference, and do not readily take meat 

 in captivity. 



Montgomery states that "from observations of the ^leno- 

 branchus in an aquarium plentifully stocked with molluscs, such 

 as Physidffi, limnseans, Paludinte, Planorhcs, Anodoiits, etc., as 



