310 
BRITISH ENTOMOSTRACA. 
gimlet in plunging itself into the flesh of the fish. He 
succeeded, however, in obtaining a specimen, which he 
describes and figures.* They bury, he says, their whole 
head or trunk in the flesh of the sword-fish. They are 
not generally confined to one part of the body, but always 
on such places as that the fin of the animal cannot reach 
them. Boccone refers this species to the Oistros, or Asilus 
marinus of Gesner, &c., and says that no figure is given 
of it by Gesner, or any of the authors who take notice of 
it. In this, however, as I have shown above, he was 
mistaken ; and had he observed the figures given by 
Gesner and Rondeletius, he would not have made the 
mistake of asserting the two species to be identical, t Its 
being found upon the Xiphias, or sword-fish, no doubt 
was the cause of the mistake. He makes, however, a very 
curious observation in connexion with this parasite. “ This 
sangsue/’ he says, “ appears to be tormented by a louse 
which I have never seen on any other animal. It is of the 
size of a pea, and attaches itself firmly to the animal/’ 
p. 292. 
Gesner, in quoting Aristotle’s description of the Asilus, 
had already observed, “ adeo nihil est quod hoste careat” 
(p. 112), a remark well illustrated by the little fact just 
mentioned by Boccone. J 
Muraltus, in the e Miscellanea curiosa siveEphemeridum 
Medico Physicarum Germanicarum Academise Naturae 
Curiosorum/ published at Nuremberg in 1,682, mentions 
that while dissecting a specimen of the Mustela Jluviatilis , 
he found an insect inserted into the eye of the fish, and 
hanging out from it. It was so firmly fixed in the eye by 
the arms, that no doubt, he says, these animals caused the 
humours of the eye to escape, and thus rendered the fish 
* Pecherches et Observations, p. 284, et sequent, tab., p. 287. 
f This animal is a species of Penella, or Pennatula, Linn. 
1 Some fleas there are that live on men. 
And these have fleas on them again ; 
Large fleas have lesser ones that bite ’em, 
Thus fleas eat fleas ad infinitum ! 
