ON THE ARRANGEMENT OF THE MAMMALIA. 183 



and Kangaroo Rats) should succeed the Pollicata, excepting that Illiger 

 could not shut his eyes against the natural connexion between the Kangaroos 

 and the other marsupials, which conclude the preceding order, and which 

 Storr, who first placed the marsupials with Man, the Simiae, and the Lemurs, 

 did not dissociate from the Linnaean genus Didelphis.* In fact, he per- 

 ceived, that the Phalangers incline to the Kangaroos ; and it is not unrea- 

 sonable to expect that the immediate links between them will yet be 

 forthcoming. This anticipation may be, indeed, entertained with the more 

 confidence, as some of the Kangaroos are not absolutely terrestrial, but 

 even arboreal. Those who scatter asunder the marsupials, make light of 

 the descriptive phrase " mastotheca ventralis" (abdominal pouch), as if' 

 the character denoted by the expression were absolutely isolated ; while, 

 in fact, it is but one of many with which it is invariably associated. f 

 The orders of Illiger stand as follow : 



ORDER I. ERECTA. Examples: Man. 



II. POLLICATA. Monkeys of the Old and New World (not distinguished 



from each other), Lemurs, and the pedinaanous 

 marsupials. 



III. SALIENTIA. The Kangaroos and Hypsiprymni. 



IV. PRENSICULANTIA. The Rodents. 



V. MULTUNGULA. Elephant, Rhinoceros, Hippopotamus, Tapir, Hog. 



VI. SOLIDUNGULA. Horse. 



VII. BISULCA. Ruminants. 



VIII. TARDIGRADA. Sloths and Prochilus. 



IX. EFFODIENTIA. Orycteropus, Ant-eaters, and Manis. 



X. REPTANTIA. Echidna, Ornithorhynchus (and Pamphractus ?). 



XL VOLITANTIA. Galeopithecus and the Bats. 



XII. FALCULATA. The Insectivora and the Carnivora, excluding Seals. 



XIII. PINNIPEDIA. Seals. 



XIV. NATANTIA. Lamantins, Duyongs, Whales, Porpoises, &c.J 



* In the establishment of the genus Didelphis, it is very obvious that Linnaeus was guided by true 

 principles. Few marsupial animals were known in his time. He looked at their great characters ; he 

 saw that they must be associated ; and his genus Didelphis ought to be regarded in the light of an 

 order, or an equivalent to the Marsupialia of Cuvier. 



t Supposing, for argument's sake, that we did not possess the information with which anatomists 

 have furnished us, as regards the internal structure of the Marsupialia, but were merely aware of the 

 fact, that a certain number of mammals, inhabiting a certain country, all agreed in the circumstance of 

 bringing forth their young prematurely; and that they all possessed a pouch, for the reception of their 

 young, we might, even then, with the knowledge of the geographical distribution of animals, be led 

 to suppose that these mammals were nearly related to each other by affinity. Accordingly, we arrange 

 them together, and compare one species with another, and what is the result ? \Ve find, variable or 

 adaptive as are the characters among them, that the most dissimilar species are linked together by inter- 

 mediate forms ; and that we cannot separate one species without doing violence to the series, nor place 

 one of the species in any other group, without doing violence to the affinities observable in that group. 

 But supposing that we now bring anatomy to our aid, as a test, what then is the result? It proclaims 

 these mammals as beings of a peculiar and very low type of structure, and forbids us to associate any of 

 them with the mammals of a higher type, as peremptorily as it does the association of the Amphibia with 

 the true Lizards, or Tortoises. 



I With respect to these orders, Illiger thus writes : " Mammalium ordines fere iidem sunt, quos 

 Cuvier et Dumeril instituerunt, aliter tamen conjuncti. Nam Pedimana cum Quadrumanis, Digitigrada 

 cum Plantigradis eodem ordine comprehendi, Manatum, Halicorem et Rytinam ex amphibiorum 

 (Pinnipedium) ordine ad cetacea translocavi; Salientium ordinem novum condidi. In serie ordinum 

 in Mammalibus naturali, multum desudavi, eosque varium in modum verti et collocavi, donee ea qua 



