180 Professor Owen, on (he [Jan. 27, 



the subclass. Such, e.g., were the cloaca, convoluted trachea, super- 

 numerary cervical vertebrae and their floating ribs, in the Three-toed 

 Sloth ; the numerous trunk-ribs in the Two-toed Sloth ; the irrita- 

 bility of tlie muscular fibre, and persistence of contractile power in 

 the Sloths and some other Bruta ; the long, slender, beak-like 

 edentulous jaws and gizzard of the Anteaters ; the imbricated scales 

 of the equally edentulous Pangolins, which have both gizzard and 

 gastric glands like the proventricular ones in birds ; the dermal bony 

 armour of the Armadillos like that of loricated Saurians ; the quills 

 of the Porcupine and Hedgehog : the brilliant iridescent colours of 

 the fur of the Cape-mole ( Chrysochlora aurea) ; the proventriculus 

 of the Dormouse and Beaver; the prevalence of disproportionate 

 development of the hind limbs in the Rodentia ; coupled, in the 

 Jerboa, with confluence of the three chief metatarsals into one bone, 

 as in birds ; the keeled sternum and wings of the Bats ; the aptitude 

 of the Cheiroptera, Insectivora, and certain Rodentia to fall, like 

 Reptiles, into a state of true torpidity, associated with a corresponding 

 faculty of the heart to circulate carbonized or black blood : — these, 

 and the like indications of coaffinity with the Lyencephala to the 

 Oviparous air-breathing Vertebrata, had mainly prevailed with 

 Professor Owen against an acquiescence in the elevation of different 

 groups of the Lissencepeala to a higher place in the Mammalian 

 series, and in their respective association, through some single charac- 

 ter, with better-brained orders, according to Mammalogical systems 

 which, at different limes, have been proposed by zoologists of deserved 

 reputation. Such, e.g., as the association of the long-clifwed Bruta 

 with the Ungidata, and of the shorter-clawed Shrews, Moles, and 

 Hedgehogs, as well as the Bats, with the Carnivora ; of the ^^Sloths 

 with the Qimdrumana ; of the Bats with the same high order ; and 

 of the Insectivora and Rodentia in immediate sequence after the 

 Linnean ' Primates,' as in the latest published ' System of Mamma- 

 logy,* from a distinguished French author. 



So far as their ordinal aflRinities are known, the most ancient Mam- 

 mals, the fossil remains of which have been found in secondary strata, 

 are either ly- or liss-encephalous, and belong either to^e Marsupialia 

 or the Insectivora. 



The Mammals exemplifying the third type of brain, were called 

 Gyrencephala,* in reference to the commonly unvoluted exterior of 

 the cerebral hemispheres: but the more general character was the 

 larger proportion of these parts, as exemplified in the small smooth- 

 brained Monkeys and Lemurs. 



The G YRENCEPiiALA are primarily subdivided, according to modifi- 

 cations of the locomotive organs, into three series, for which the Lin- 

 nean terms may well be retained ; viz., Mutilata, Ungulata, and Un- 

 guiculata, the maimed, the hoofed, and the clawed series. 



These limb-characters can only be rightly applied to the gyren- 

 cephalous subclass ; they do not indicate natural groups, save in that 



* yvj ocv, to "wind about ; sy}i£(pocAO(, brain. 



