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 hi 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.;}: 



Muraltus, in the ' Miscellanea curiosa siveEphemeridum 

 Medico Physicarum Germanicarum Academige Naturae 

 Curiosorum,' published at Nuremberg in 1682, mentions 

 that while dissecting a specimen of the Mustela Jiuviatilis, 

 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 



* Rechercbes et Observatious, p. 28i, et sequent, tab., p. 287. 

 f This animal is a species of Penella, or Peuuatula, Linn. 

 % 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 cat fleas ad injinitinn ! 



