324 THE ZOOLOGIST. 



A Carnivorous Plant preying on Vertebrata.— An interesting dis- 

 covery lias been made during the last week by Mr. G. E. Simms, son of a 

 well-known tradesman of Oxford. It is that the bladder-traps of Utri- 

 cularia vulgaris are capable of catching newly-hatched fish and killing them. 

 Mr. Simms brought to me for examination a specimen of Utricularia in a 

 glass vessel, in which were numerous young Roach newly hatched from 

 a mass of spawn lying at the bottom. Numbers of these young fish were 

 seen dead, held fast in the jaws of the bladder-traps of the plant. I had 

 never seen Utricularia before, and am indebted to my colleague Prof. 

 Burdon Sanderson for the identification of the plant and a reference to 

 Cohn's researches on it. Mr. Simms supplied me with a fresh specimen 

 of Utricularia in a vessel with fresh young fish and spawn, and in about 

 six hours more than a dozen of the fish were found entrapped. Most are 

 caught by tlie head, and when this is the case the head is usually pushed 

 as far into the bladder as possible till the snout touches its hinder wall. 

 The two dark black eyes of the fish then show out conspicuously through 

 the wall of the bladder. Rarely a specimen is seen caught by the tip of the 

 snout. By no means a few of the fish are, however, captured by the tail, 

 which is swallowed, so to speak, to a greater or less distance, and I have 

 one specimen in which the fish is caught by the yelk-sac. Three or four 

 instances were observed in which a fish had its head swallowed by one 

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

 forming a connecting bar between the two bladders. I have not 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 fore part 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. Darwin, in his 

 account of the trapping of Crustacea, worms, Ac, by Utricularia, states 

 that he was not able to observe the actual occurrence of the trapping of an 

 animal, although Mrs. Treat, of New Jersey, often did so. I think 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 quadrified 

 processes by which the bladders of Utricularia are lined "project obliquely 

 inwards and towards the posterior end of the bladder," has something to do 

 with the mechanism by which tlie small fisli become so deeply swallowed, 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 in utilising each fresh struggle of the captive for the purpose of 

 pushing it further and further inwards. On cutting open longitudinally 

 some of the bladders containing the heads and foreparts of the bodies of 

 fish, and examining their contents, I found the tissues of the fish in a more 

 or less slimy deliquescent condition, no doubt from decomposition, for 

 Mr. Darwin failed to detect any digestive process in Utricularia. The 



