the natural Distribiiiion of Insects and Finini. 59 



tas imperfectionem potius indicat; perfectissima enim sunt in 

 qu^vis sectione ab omnibus aliis remotissima. Sic perfectissima 

 animalia et vegetabiHa, qua maxime a se invicem remota ; infi- 

 ma, quorum limites confluunt." Hence it follows, that the cew- 

 trum, or perfection of a group, is in fact that part of the circum- 

 ference of the circle of affinity which is farthest from the neigh- 

 bouring group, and exactly the same thing with what in the HorcE 

 Entomologica has perhaps more happily been called Type. 

 . Indeed the confusion arising from the use of the word centrum, 

 as applied to a point in the circumference of a circle, is still in- 

 creased by applying the word radii to those groups likewise in the 

 circumference which lead from one centrum or type to another, 

 and which I have termed annectent groups*. The use of these 

 terms centrum and radii is the more unfortunate, as our author 

 never for a moment takes them in any other sense than that in 

 which I have used the expressions type and annectent groups. 

 When, therefore, he says that in every group, whether class, 

 order, &c. there are a centrum and radii, we must understand him 

 as meaning, that there are in everj^ circle first a type or normal 

 form expressing the perfection of the superior group to which it 

 belongs ; and secondly, annectent groups connecting this type 

 with other groups. Or, to take his own words, " In centrum quod 



dom, wliich I have given in Horic Entomologicec, p. 203, I may add the botanical 

 authority of Professor Schweigger. " Nee eliam genera et ordines plantarum in li- 

 neam a cryptogamicis ad dicotyledoneas progredientem ita disponi possunt, ut familia 

 qusevis priBcedentis structuram magis evolutam prsebeat. Vix uUus de vegetabilium 

 serie usitata, a colyledonum numero deducta, affirmat, plantas dicotyledoneas omni 

 ratione tnonocotyledoneis esse anteponendas." p. 6. J)c Plantarum classijlcatiorte 

 naturali Disquisitionibns Jnatomicis el P hysiologicis stabiUenda Commentatio, jiuc- 

 tore A. F. Schweigger, S)X. Regiomonti 1820. 



* There are several other terms used by M. Fries to designate his groups, and which 

 differ from those employed by me to express the nature of similar groups. Thus, his 

 intermediate genera are my osculant genera ; his subordinate genera are my li/pes of 

 form or sub-genera, Sue. 



1 2 species 



