NOTES ON I'ONTOBDELLA MUBICATA. 331 



In The Aquarium Naturalist Professor Eymer Jones writes that the 

 skate-leech becomes more active at the approach of evening, and that 

 it rejects all subsistence when in confinement, though extremely 

 voracious in the natural state. My Pontohddla, however, was neither 

 more nor less active in the evening than at other times in the twenty- 

 four hours. He certainly abstained from food during the first four 

 months of his residence with me, not decreasing in size or appearing 

 at all out of health during the whole of that time, so that I began 

 to think he must have some miraculous power of fasting. I tried him 

 with all sorts of food, such as raw meat, live shell-fish, live earthworms, 

 live and dead wrasse, etc., but he would have none of them. At last, 

 one day a flounder and a skate (both young) died within a day of each 

 other in another tank, so I placed the flounder, who was only just dead, 

 in the leech's tank, just under the latter's head. As usual, when the 

 leech became aware of my hand being in the tank he began moving 

 his head about, and in doing so touched the flounder several times ; 

 however, he took no more notice of it than if it had been a piece of 

 rock, so I gently detached him from his place, and put him on the back 

 of the flounder ; the leech, however, instantly got off it and returned 

 to his corner. I therefore concluded that live flat-fish were essential to 

 him if he would feed at all in captiviy, for I did not think that one 

 species of flat-fish would be less acceptable to him than another. 



However, the skate died the next day, and I dropped him into the 

 leech's tank, without expecting the latter to take any notice, any more 

 than he had of the dead flounder. To my surprise, the skate had 

 hardly touched the bottom of the tank when the leech detached his 

 base and cast himself upon the skate's body, where he immediately 

 fixed his base and sat upright with his head doubled down in the usual 

 way ; after a few minutes, he bit the skate's back in several places, 

 evidently making vigorous but unsuccessful efforts to extract blood. 

 His labours lasted about half an hour, and he then returned to his 

 old corner, and took no further notice of the skate. 



I observed that when about to attack his prey he did not move in 

 his usual way, which is that of a fresh-water leech, viz., by first fixing 

 his head and then drawing up his base after it. He simply detached 

 his base, fell to the bottom of the tank, and extended himself till he 

 was over the skate's body, then drew up the rest of his body till it 

 lay sideways in a loose coil on the skate, and then fixed his base, not 

 his head, on the lower part of the skate's wing. 



Probably this method of attack is less alarming to a live fish than 

 if the leech first seized with his head. 



After this episode with the dead skate, I moved the leech into a 

 much larger and deeper tank, wherein were many blennies, gobies, 



NEW SERIES. — VOL. V. NO. 3. Y 



