260 BULLETIN OF THE UNITED STATES FISII COMMISSiON. 



bladder-trap and its tail by another adjacent one, the bodj' of the fish 

 forming a connecting bar between the two bladders. 



I havenot been able to see a fish in the actual process of being trapped, 

 nor to find one recently caught, and showing by motion of the forepart 

 of its body signs of life. All those trapped were found already dead, 

 but I have had no opportunity of prolonged observation, and it will be 

 remembered that Mr. Darwiu in his" account of the trapping of Crus- 

 tacea, worms, &c., by Utricuhrria, states that he was not able to ob- 

 serve the actual occurrence of the trapping of an animal, although Mrs. 

 Treat, of New Jersey, often did so. I tliinlv it probable that the fact 

 described by Mr. Darwin, and which is easily verified, that the longer 

 of the two pairs of projections composing the quadrifid processes by 

 which the bladders of UtricuJaria are lined "project obliquely in- 

 wards and towards the posterior end of the bladder," has something 

 to do with mechanism by which the small fiyh become so deeply swal- 

 lowed, so to speak. The oblique processes, set all towards the hinder 

 end of the bladder, look as if they must act together with the spring 

 valves of the mouth of the bladder iu utilizing each fresh struggle of 

 the captive for the purpose of ])ushing it further and further inwards. 

 On cutting open longitudinally some of the bladders containing the 

 heads and forei^arts of the bodies of fish and examining their contents, 

 I found the tissues of the fish in a more or less slimy deliquescent con- 

 dition, no doubt from decomposition, for Mr. Darwin failed to detect any 

 digestive process in Utricularia. The quadrifid processes were bathed 

 iu the slimy semi-fluid animal substance, and the ])rocess(S themselves 

 appeared to contain abundance of fine gianuhir matter, possibly the re- 

 sult of absorption, but the large quantity of surrounding animal matter 

 present rendered the observation uncertain. The usual swarms of in- 

 fusoria were present in the decomposing matter. 



Specimens of the Utricularia with the little fish fast in the bladder- 

 trap, and their heads or tails hanging out, can be well preserved iu 

 spirits, and show the conditions well, notwithstanding that the i^lant 

 becomes colorless, and there is no longer the marked contrast between 

 the glistening white dead fisli and the green bladders, which in the 

 fresh condition rend« rs the combination of the trap and ))rey conspicuous. 



Mr. Simms, by whose permission 1 write this, intends shortly to pub- 

 lish an account of his observations himself. I have advised him to en- 

 deavor to prepare spirit specimens of Utricularia ])lants with nunierous 

 trapped fish in situ for sale to those interested in the matter who my 

 care to apply for them.* His address is 37 Broad street, Oxford. 



* Specimens of the entrapped fisli were received from Professor Moseley by 1 lie United 

 States Fish Commission June 'J, and arc deposited in the National Museum. The 

 Utricularia is a large, rootless, water-plant, which lloats freely iu the watei'. Its leaves 

 bear the small bladder's which entrap the fish fiy. Eleven ^pecie8 are enumerated iu 

 the Fish Commission Bulletin, 188:}, p. 2(50, as useful in carp noiids. While these do 

 not include the vulgaris, it is probable! that some of these mny have tlie same ability 

 to catch the small fish. In that case even these plants nnist be excluded from carp 

 ponds. -C. W. S. 



