286 



PROCEEDINGS OF THE ACADEMY OF 



Froboscidia. Diprotodoniidse. 



Two inferior incisors ; molars with two cross-crests ; size huge. 

 a. Two rudimental lateral incisors above. 

 * * Diprotodon. 



aa. ? One pair of incisors only above ; a trunk. 

 Dinotherium. 



V. No canines ; two pairs of cutting incisors. 

 a. Three true molars. 

 Rodentia. 



aa. Four true molars. 



* * 



Rhizophaga. 



The parallels are in this case very imperfect in details, and but few worthy 

 of the name can be made. They are, however, illustrative of a remote hetero- 

 logy, sufficiently remarkable to have claimed the notice of naturalists for man)» 

 years.* I also have little doubt but that future palteontological discoveries 

 will increase the number of parallels, but bring to light truly heterologous 

 generic terms of the Marsupial series. Predictions of this kind have been on 

 many occasions fulfilled (e. g.^ some of D'Orbigny's among the Cephalopoda), 

 and I look with confidence to the ultimate demonstration of that heterology 

 here, which has been already seen in the Batrachia and Reptilia. 



The homologous groups of the Catarrhine and Platyrrhine Quadrumana are 

 measured as follows : 



Tailless. 



Tail short. 



Long tail. 



Thumb developed. 



Thumb rudimental. 

 Thumb none. 



Catarrhini. 



Andropithecus. 



Simla. 



Hylobates. 



Cynocephalus. 



Macacus. 



Cercopithecus. 



Semnopithecus. 

 Colobus. 



Platyrrhini. 



Brachyurus. 



Lagothrix. 

 Mycetes. 



Brachyteles. 



Ateles. 



I append two homologous series, represented by the Nautilea and the Ammo- 

 nites of the Tetrabranchiate Cephalopoda, which are distinguished, the first 

 by the simple septa and the siphon central or marginal ventral ; and the second 

 by the complex and folded septa and siphon central or marginal dorsal. The 

 parallelisms have been noted by Barrande, Bronn, and many conchologists, 

 who can furnish a much more full table than the following, from the most re- 

 cent sources : ^ 



Nautili. Ammonites. 



A. The shell straight, unwound. 

 Orthoceras. 



B. The shell more or less curved or wound. 

 a.. Simply curved. 



Cyrtoceras, \ 



Phragmoceras, J 



etet. A more or less straight portion, folded on the remainder. 

 (i. Folded portion in close contact with remainder. 



Baculites. 



Toxoceras. 



* We owe very many observations on the Marsupials to Owen. 



[Oct., 



