30 HOW PLANTS USE ANIMALS. 



Mrs. Treat, in New Jersey, ex})eriiuented on Ultricularia clan- 

 destina, and gives many interesting details. "There is a 

 depression," she says, "at the entrance of the utricle, a })retty 

 vestibule that seems to attract the little animals into the inviting 

 retreat, where just beyond is a fatal trap or valve, which, if 

 touched, springs back and engulphs the unwary adventurers, never 

 more to be released. I was very much amused in watching a 

 water-bear (Tardigrada) entrapped. It slowly walked around 

 the utricle, as if reconnoitring — very much like its larger name- 

 sake; finally it ventured into the vestibule and soon, heedlessly, 

 touched the trap, when it was taken within so quickly that my 

 eyes eould not follow the motion. The utricle was transparent 

 and quite empty, so that I could see the behavior of the little 

 animal very distinctly. It seemed to look around as if surprised 

 to find itself in so elegant a chamber; but it wjis soon quiet, and 

 on the morning following it was entirely motionless, with its 

 little feet and claws standing out stiff and rigid. The wicked 

 plant had killed it very much quicker than it kills the snake-like 

 larva." Mrs. Treat also describes how these plants entrap the 

 larvae of the mosquito, an employment in which ^ve wish it 

 al)undant success. 



Darwin examined the bladders uf a great many specimens of 

 U. neglecta and found they contained four, five, eight, ten 

 entomostracan crustaceans, and frequently other animals in the 

 same bladder. One of our Canadian species (U. vulgaris), 

 abundant in ditches, pools, lakes and slow streams from New- 

 foundland and Halifax to Vancouver, bears a Ijad reputation for 

 trapping and destroying young rish. Young salmon, bred in 

 hatcheries, when set free in the lakes are caught around the body 

 in the mouth of the bladder and held fast till they perish. Five 

 to ten crustaceans have been found in single utricles. 



2. The genus Pinguicula (Butter- wort) contains about thirty 

 species, of which three are credited to Canada. Of these only 

 one (Pinguicula vulgaris) is of common occurrence, being distri- 

 buted from Newfoundland and Labrador westward along the St. 

 Lawrence and the Great Lakes, and onward across the continent 



