240 



tion, the fundamental fact upon which it was built up being an 

 accidental one. 



Besides this, another circumstance had struck me, namely, that 

 the ovarian eggs of an Annelid were illustrated by Mr. Desor, 

 almost side by side with those of Ascidia, without any reference 

 being made to Biogen. This is explained by the fact, that the 

 eggs of Annelids can be observed easily without any compression 

 to isolate them. 



As for the comparison the author has established between the 

 formation of the eggs in general and that of heavenly bodies, 

 according to the nebula hypothesis, it is easy to see that it no 

 longer requires controverting. 



Thus, the great law of universal attraction is by no means at 

 the bottom of organized bodies ; and with regard to the move- 

 ments of the larva of some few invertebrated animals, there 

 is nothing in them which resembles the phenomenon of the 

 motion of the celestial bodies. (See p. 85.) 



Dr. Burnett read a paper upon the external parasites of 

 warm-blooded animals. From his study of these insects, 

 he said he had established to his satisfaction the following 

 facts : 



1st. That although there are single species peculiar to par- 

 ticular animals, there are others which are found in different 

 species of the same genus, as is the case in the parasites living 

 on birds of the genus Larus (Gulls) and the diurnal birds of 

 prey. 



2nd. The parasites of the human body confine themselves 

 strictly to particular regions ; when they are found elsewhere it 

 is the result of accident. Thus, the Pediculus capitis lives on 

 the head ; the P. vestimenti upon the surface of the body ; the 

 P. tdbescentium on the bodies of those dying with marasmus ; 

 and the Phthirius inguinalis about the groins, armpits, mouth, 

 and eyes, or the homologous parts of the bady. 



From an examination of the structure of these animals. Dr. 

 Burnett was of opinion that they should be placed in an order by 

 themselves, closely allied to the Insecta ; they number about 250 

 species, the Mandibulate parasites occupying the highest, and 

 the Haustellate the lowest position in the order. 



