1885.] Progressive and Retrogressive. 347 
yyyy. Both tarsal and carpal series more or less alternating. 
Os magnum not supporting scaphoides; cuboid supporting astragalus; superior 
molars tritubercular, ss .e ss soubre tase ; 8. Amblypoda. 
Os magnum supporting scaphoides; superior molars quadritubercular 
9. Diplarthras 
BBB. Anterior limbs with flexible joints. Ungual phalanges compressed 
and pointed? (Unguiculata). 
e. Teeth without enamel; no incisots. 
Limbs not volant; hemispheres small, smooth 10. Edentata. 
es, Teeth with enamel; incisors present, 
No postglenoid process ; mandibular condyle round; limbs not volant; hemispheres 
small, smooth. ......essees 1, Rodentia. 
Limbs volant; hemispheres small, smooth 12. Chiroptera. 
A postglenoid process ; mandibular condyle transverse ; limbs not volant, no scapho- 
lunar bone ;3 hemispheres small, smooth bi ean 13. Bunotheria.® 
A postglenoid process; limbs not volant, with a scapholunar bone; hemispheres 
larger, convoluted > ...essssssosvsrosseseeceoseseeovesresee 14. Carnivora. 
Paleontology has cleared up the phylogeny of most of these 
orders, but some of them remain as yet unexplained. This is 
the case with the Cetacea, the Sirenia and the Taxeopoda. The 
last-named order and the Marsupialia can be supposed with much 
probability to have come off from the Monotremata, but there is 
as yet no palzontological evidence to sustain the hypothesis. 
No progress has been made in unraveling the phylogeny of the 
Cetacea and Sirenia. The facts and hypotheses as to the phy- 
logeny of the Mammalia may be represented in the following 
diagram ia 
Diplarthra Hyracoidea Insectivora Rodentia Chiroptera 
Proboscidea \ Anthropoidea / Edentata | Carnivora 
| 
Amblypoda Quadrumana | Tillodonta 
Tzniodonta | Creodonta 
Cetacea Condylarthra 
Marsupialia 
Monotremata 
1 Except Pantolestes. This order includes the suborders Perissodactyla and Artio- 
la. 
2 Except Mesonyx. 
3 Eri 
naceus. 
4 With the suborders Insectivora, Creodonta, Tæniodonta and Tillodonta. 
