NUMBER AXD BANK OF GROUPS. 273 



of insects {Annulosti), pointing out the probable station 

 of the Scarab(Eus Sacer of Mac Leay. 



H\BPL'L\ Vexilu'm, Zool.Ill.2. pi. 77. Scarab.sus Sacer MacL. ' 



1. Kingdotn. Animalia. 1. Kingdoyn. Animalia. 



2. Sub-kingdom. Mollusca L. 2. Sub~kingdum, Annulosa. 

 {Molliisca, Uadiala, Acrita, 

 MacLA 



3. Class, Testacca. (Mollusca 3. Class. Ptilota Arist. 

 MacL.) 

 4. Order. Gasteropoda Cuv. 4. Order. Coleoptera Lin. 

 5. Tribe. Zoophaga. 5. Tribe. Chilognathiform 



(MacL.) 

 6. Family. Volutidae. 6. Family. Scarabjeid'ae Sw. 



(Petalocera Saprophaga 

 MacL.) 

 7. Sub-family. VolutinEP. 7. Siib.family Scarabs na? 



Sw. (ScarabaeideB MacL.) 

 S. Genus. Harpula Sw. 8. Genus. ScarabiEUs 



MacL. 

 9. Sub-genus. Harpula /i)-o/7fr. 9. Sub-genus. Helio- 



cantharus Auct. 

 (Scarabteus proper.) 



The demonstration of all these groups cannot, of course, 

 now be entered upon, although full details will be given 

 in their proper place. These, however, are the results ; 

 and illustrate, in the most intelligible manner, the deter- 

 minate number of graduated ranks of circles in the 

 animal kingdom. 



{So"^.^ Although we have not yet detected in the 

 scheme of nature more than nine gradations of circles, it 

 by no means follows that all these are constantly to be 

 met with in every circle of superior magnitude; as, for 

 instance, in classes or orders. This inequality in the 

 contents of two groups of the same analogical rank has 

 already been fully accounted for.* Sometimes, as in 

 the order Rapfores-, the primary groups do not ajjpear 

 of a higher rank than the families of the Inaessore-s ; and 

 even of these, one, if not two, entire families are extinct. 

 Aberrant groups are almost always fewer, both in j^oint 

 of numbers and of divisions, than such as are typical; 

 and sometimes an aberrant genus, instead of having 

 many species, so as to contain its own types of form, 

 will be only represented by a single individual. This, 



• See Preliminary Discourse on Nat. Hist p.;231- 



