ANIMAL KINGDOM. 319 



On the examination of this sketch, we are at first struck 

 with the analogy which opposite points of the same circle 

 bear to one another, — an analogy sometimes so strong 

 that it has been mistaken for a relation of affinity; and in- 

 deed I am still unable to state whether this be not the 

 fact, and that the opposite points of the curve, if I may so 

 express myself, do not meet each other. Thus the re- 

 semblance which the intestinal Acrita or Monoo-ena of 



to 



Latreille bear to the Nematoidea of Rudolphi and the 

 Annelides, need not be descanted on, nor the affinity 

 which the Cirripeda, according to some naturalists, appear 

 to have with the Brachiopod Mollusca. It will be suffi- 

 cient to state, that as this peculiarity of natural distribution 

 was detected by analysis in the former part of this work, 

 and the use to be made of it was visible among the Peta- 

 locera; so the discovery of it served to prevent my falling 

 into several mistakes, which I could not otherwise have 

 avoided in deciding between relations of analogy and affi- 

 nity, as they exist in the more general groups. The qua- 

 druped Reptiles may in this way be separated from the 

 Mammalia by the intervention of Birds on one hand and 

 of Fishes on the other; and yet Dumeril may possibly not 

 be far wrong in urging that the paradoxical Qrnithorhyn- 

 chus bears a nearer relation to Reptiles than to Birds. But 

 my province more peculiarly is Entomology; and this pro- 

 perty of a distribution which for convenience only we 

 have considered as circular, will serve to make the hexa- 

 pod Acarida approach to the Anoplura of Leach, as ap- 

 pears to be the case in nature. 



The next observation to be made is on the nature of 

 the five osculant groups, by Avhich we may have per- 

 ceived the great divisions of animal life to be connected 



