Xll PREFACE. 



were diagnostic of certain families of Vertebrata. It is 

 easy to say whether they are belonging to quadruped or bird, 

 but more difficult to pronounce the peculiar family of either, 

 as some genera of each division appear perfect cosmopolites; 

 as for instance, the genus Pediculus of Linn, (since divided 

 into Pediculus and Haematopinus), besides infesting Man, 

 is also found in the orders Quadrumana, on Monkeys ; 

 Rodentia, on the Squirrel, Hare, Rabbit, Water Rat; 

 Carnivora, on the Dog and Seal ; P achy der mat a^ on the 

 Swine, Ass, and Camel; Ruminantia, on the Deer, Ox, 

 and Buffalo. The genus Nirmus again is very extensively 

 spread, infesting every order of birds but the Gallinacea. 

 Docophorus all but Gallinacea and Columbidce ; Lipeurus 

 infesting the orders Gallinacea, Grallce, Palmipedes, and 

 Accipitres, while on the other hand, a few, as I have stated, 

 are nearly certain indexes to the families Eureum only on 

 Chelidones, Trinoton only on Palmipedes, Goniocotes and 

 Goniodes only on Gallinacea and Columbidce, Gyropus 

 only on the Guinea Pig in this country. Dr. Burmeister 

 enumerates a species also from the Ai (Bradypus tridac- 

 tylus), and lastly, the genus Phthirius on Man. 



From the great diversity in colour and size during life, 

 and alteration of form and change of colour after death, 

 considerable difficulty has been felt in coming to correct 

 conclusions as to the proper form and colour of individual 

 species, and even now the author is not without fear, that 

 he may be charged with error. To this, however, he has 

 only to reply, that as far as possible he has endeavoured to 

 avoid misrepresentation, by re-drawing many species when 

 fresh specimens could be procured, and even after some 

 had been committed to copper, he has been compelled to 

 re-engrave them. He therefore hopes upon this point to 

 be criticised with mercy : again, so considerable is the dif- 

 ference that exists between the early and adult state of 

 many species, that their identity could only be inferred by 



