332 NOTES ON POSTOIiDELLA MUIilCATA. 



wrasse, etc., thinking that he might secure a wrasse when lying half 

 on its side asleep at nights, as is the frequent custom of these fish. 



The fish displayed no fear of the leech ; on the contrary, several of 

 them bit at him when he was first put in. 



The leech, however, seemed extremely alarmed at the fish, and at 

 once secreted himself between two large stones at the bottom of the 

 tank, where he remained hidden for about a week without moving. 

 I then introduced three young live skate into the tank, and extracting 

 the leech from his hiding-place, put him on the back of one of them ; 

 he took no notice of it however, but immediately escaped to a rock 

 fixed to the side of the tank. I left him there for the night, but in 

 the morning the leech was fixed, as to his base, on the lower part of 

 the wing of one of the live skate, in exactly the same place where 

 he had settled on the dead skate. 



There were traces of blood on the skate's back, and about an hour 

 later the leech had fixed his mouth on the wing, and immediately in 

 front of the leech's mouth there was a semi-circular mark of blood. 



The two other skate died in the course of the day, but the third 

 skate lived on for about twenty-four hours with the leech on his 

 back. The latter must have extracted a quantity of blood, but he 

 did not swell as does a fresh-water leech when gorged. 



When Pontohdella had had enough he would raise himself upright 

 in his usual position, and with his base still fixed to the skate, until 

 he felt ready for another attack. 



Finally he got off the skate, and hid himself completely under 

 a stone, and a quarter of an hour after the leech had disappeared 

 the skate died. The latter would probably have borne the leech's attack 

 longer, had it not been enfeebled by a recent journey from Plymouth 

 to London. 



The leech remained in hiding for about a month after his meal, 

 and I then removed him and the other animals from London to the 

 country. 



He had always appeared to dislike heat, and unfortunately, on 

 arriving in the country, he was placed in a shallow vessel, the water 

 in which had been greatly heated by the sun. He at once lost 

 the power of attaching his base, and lay for three or four days on 

 his side, coiled like a watch-spring, and then died. Given a live 

 skate or so a year and cool water, I believe Pontohdella could be 

 kept alive for an indefinite period. 



