A LILLIPUTIAN MONSTER. 521 



matter stained with these pigments. Other species have been 

 noticed, but they are less common, and some are rarely met with. 



A single individual may be thus described : There is the body, 

 like a thick thread, of varying length up to an inch. At the foot 

 the substance is slightly expanded into a small disk, with which 

 the creature fixes itself to some surface ; at the top is a series of 

 arms or tentacles, thin, threadlike, and arranged symmetrically 

 around the end of the stem, which is the mouth. These tentacles 

 vary in number, the green hydra having from six to ten, and the 

 brown one from seven to twelve. As the trunk sways this way 

 and that in a slight degree, and the tentacles twist about, the 

 sight is a curious one and well worth while watching. The arms 

 have the power of contracting, and sometimes look like little 

 buds around the mouth ; and the trunk itself will also sink down 

 until it seems to be a small mass of jelly. 



The trunk is nothing but a stomach. There are no lungs, no 

 liver, no heart, no intestines, no nervous system. All there is 

 consists of two layers of tissue, with a very delicate layer be- 

 tween. The trunk and the tentacles are alike in structure, and 

 are simple hollow tubes. If the latter are examined with a mag- 

 nifying glass, they are found to be covered with little warts, 

 which are technically called "urticating" or stinging organs. 

 These consist of an oval capsule, the top of which is turned back 

 into itself so as to form a cavity in which there lies a thread 

 coiled up, while round the edge of the cavity are four little darts. 

 In this introverted capsule the thread lies bathed in a poisonous 

 secretion, and the darts are 

 nothing more or less than poi- 

 soned arrows. The opening is 

 provided with a sort of trigger, 

 so that when any substance is 

 pressed against it the capsule 

 is flung outward, the thread is 

 cast round the opposing body, 

 and the poisoned arrows are 



projected into its Substance if FlG - 3. LASSO CELLS OF THE HYDRA AND SEA 

 ... , , . ANEMONE:'!, piece of one of the hydra's 



It IS penetrable. arms? showing the cells crowded in it; 



The hydra lives on minute 2 > ne of tne c* 3118 ; 3 * ^ 6 same el1 after 

 aquatic creatures, and is ex- bursting open ; 4, lasso ceil 



clusively carnivorous. Attached to its moorings, it spreads its 

 arms in every direction with a searching motion ; and although 

 the two commonest forms can not explore at a much greater 

 distance than the height of the body, the " fuscous " species one 

 of the rare forms has tentacles which can reach some seven or 

 eight inches. As soon as a victim touches the subtle angling 

 line it is seized by it, enveloped in the threads, and struck by the 



VOL. LI. 40 



