July 24, 1884] 



NA TURE 



2 95 



Gurney, through whose instrumentality this splendid 

 collection ha= been brought together. The author com- 

 menced in 1875 an elaborate review of Mr. Sharpe's volume, 

 giving a vast amount of additional information, principally 

 founded upon the series of Kaptores contained in the 

 Norwich Museum. The complete list of the birds of prey 

 which Mr. Gurney has now published contains an exact 

 reference to these numerous critical papers in Mr. 

 Sharpe's volume, but adds some of the principal synonyms, 

 and gives the number of specimens contained in the Nor- 

 wich Museum. The publication of this volume is certain 

 to have one effect, which will take the form with all 

 ornithologists of a hope that Mr. Gurney may feel able to 

 continue his " Catalogue' of the Raptorial Birds in the 

 Norwich Museum," of which one part appeared some 

 years ago ; as it is certain that everything that emanates 

 from his pen will be received with the greatest respect by 

 his brother ornithologists, who have so long looked up to 

 him as the greatest authority on the birds of prey. 



UTRICULARIA VULGARIS 

 T T was proved many years ago that several of the 

 *■ aquatic and terrestrial plants distributed over various 

 quarters of the globe preyed upon flies, larva;, worms, 

 crustaceans, and other species of small invertebrates. 



For the greater part ot the knowledge we have already 

 received on this head we are indebted to the researches 

 and experiments of Mr. Darwin, and I would refer any 

 of my readers who may feel interested in the subject to 

 his " Insectivorous Plants." 



But until a few weeks since, when it was discovered 

 by myself, and noted in Nature by Prof. Moseley, 

 that the bladder traps of the Utricularia vulgaris 

 (Fig. 1) caught and destroyed newly-hatched fish, it 

 was unknown that any of the recognised carnivorous 

 plants possessed the power of also entrapping vertebrate 

 animals, no single instance of the kind having been re- 

 corded by previous observers ; yet it might at once have 

 been naturally inferred, that, provided the experiment was 

 made with creatures of a strength and size proportionate 

 to the capacity of the organs of capture belonging to the 

 plant, their action in every case would be precisely the 

 same on either vertebrates or invertebrates. The Utri- 

 cularia vulgaris, together with several other members of 

 the same family bearing the generic name of Utricularia, 

 and the specific, neglecta, major, minor, and clandesfina, 

 are very local in their habitat, growing in isolated patches 

 in ponds and sluggish ditches, the type of place invariably 

 selected by coarse fish to deposit their ova. This at once 

 constitutes it as great an enemy to the small fry as the 

 water-fowl and otters are to the larger fish in the streams, 

 because for a considerable period after they emerge from 

 the egg the young fish remain in the shallow water, and 

 during this time innumerable quantities must be killed by 

 the vesicles of the Utricularia. 



Since I have been acquainted with the plant, I have 

 noticed several peculiar circumstances in connection 

 with it, which appear to have been entirely overlooked by 

 all the botanical writers whose works I have consulted. 



In the first place I have never seen it growing, unless 

 displaced by the action of the wind, except on the darkest 

 and shadiest side of the pond from whence I obtain my 

 specimens, and then it is almost invariably hidden beneath 

 other aquatic vegetation, as if its deeds caused it to shun 

 the light. It also exhibits the same tendency to avoid 

 particular spots which frequently is evinced by snakes in 

 selecting only one side of a field or part of a hedge to 

 the entire exclusion of the remainder, and by fish in 

 choosing the dirtiest and most unlikely ditches as a 

 spawning bed in preference to those which are cleaner 

 and apparently in every respect better suited to the 

 purpose. 



I am of opinion that an excess of light is prejudicial to 



the plant, because, if when kept in an aquarium it is 

 exposed to the full glare of the daylight, the valves 

 appear to lose their elasticity, and the vesicles become 

 detached from the stem, and drop off. 



Another predominating cause for this strange habit of 

 growing in only one or two spots may perhaps be 

 ascribed to this, that wherever I find the Utricularia 

 there is always a luxuriant mass of Conferva; around it 

 which harbours numberless insects, and, having no roots 

 at any time of its life, is entirely dependent upon its 

 vesicles for its sustenance ; hence it only flourishes where 

 prey is plentiful. 



In confinement it is impossible to keep it in a healthy 

 state unless the glass is darkened ; and as nearly as possible 

 its artificial condition is assimilated to its natural one. 

 Where young fish are kept, it is anything but a desirable 

 inmate of the vessel in which they are confined. One 

 eminent piscicultural authority states that he had several 



plants in his aquarium with some young axolotls, and he 

 noticed that the small salamanders gradually disap- 

 peared ; now he can give a very good guess where they 

 went to. _ 



My friend Mr. Kelson, who has recently had charge of 

 my aquariums during my absence from home, agrees 

 with me that the foliage possesses some poisonous pro- 

 perties detrimental to fish. Whether it does so or not I 

 hesitate to assert, but all I know is that out of a batch of 

 young roach placed with some freshly-gathered Utricu- 

 laria, many of them in a little while lay dead on the 

 branches. 



With regard to its method of catching insects or any- 

 thing upon which it preys, I believe that the processes 

 are armed with tiny spines similar to the recurved teeth 

 of a pike, or the serrations of an awn of barley, and 

 these utilise the struggles of the creature caught to push 

 it further on but prevent its return. 



When a fish once touches one of the processes, whether 



