Reviews — R.-Lydekker's Catalogue, Fossil Mammalia. 175 



III. — Catalogue of the Fossil Mammalia in the British Museum 

 (Natural History), Cromwell Road, S.W. Part II. 1 Con- 

 taining THE ORDER UnGULATA, SUB-ORDER ARTIODACTYLA. By 



Richard Lydekker, B.A. 8vo. pp. i.-xxii. and 3241, illus- 

 trated by 39 Woodcuts. (London, 1885, printed by Order of 

 the Trustees.) 



WITH praiseworthy zeal Mr. Lydekker has finished another 

 volume of the Catalogue of Fossil Mammalia in the Geolo- 

 gical Department of our National Museum ; indeed we are assured 

 a third part is now actually passing through the press and will be 

 issued this Spring. 



The present section is a very large one (nearly 350 pages in 

 extent), and is illustrated by thirty-nine woodcuts. It is confined 

 entirely to one sub-order of the Ungulata, or hoofed-animals, the 

 Artiodactyla, or even-toed Herbivora. In this sub-order are in- 

 cluded the Bovidce, Giraffidce, Cervidte, Camelidce, Tragvlida, the 

 Suidce, Phacocliceridce, and Hippopotamidce, all of which families have 

 living representative species ; also the families Dichodontidce, Coeno- 

 theriidce, Anoplotheriidce, Oreodontidce, Merycopotamidce, Anthraco- 

 theriidcs, Chcsropotamidce, and Lisiriodontidcs, all the species of which 

 are extinct. The following definition of the Artiodactyla may be 

 acceptable. 2 In this sub-order the premolar and molar teeth are not 

 alike, the former being single, and the latter two-lobed. The last 

 lower molar of both the first and second dentition is almost in- 

 variably three-lobed. The nasal bones are not expanded posteriorly. 

 They have no alisphenoid canal. The dorsal and lumbar vertebras 

 together are always nineteen, though the former may vary from 

 twelve to fifteen. The femur is without a third trochanter. The 

 third and fourth digits of both feet are almost equally developed and 

 their ungual phalanges ai - e flattened on their inner or contiguous 

 surfaces, so that each is not symmetrical in itself ; but when the two 

 are placed together, they form a figure symmetrically disposed to a 

 line drawn between them. In other words, the axis or median line 

 of the whole foot is a line drawn between the third and fourth digits, 

 while in the Perissodactyles (uneven-toed Ungulates) it is a line 

 drawn down the centre of the third digit. The distal articular sur- 

 face of the astragalus is divided into two nearly equal facets, one for 

 the navicular and one for the cuboid bone. The calcaneum has an 

 articular facet for the lower end of the fibula. 



The Artiodactyla are naturally separable into two very well marked 

 subdivisions, namely : — 



A. The Selenodonta — including the numerous extinct genera and 

 also the existing types of true Ruminants, and 



B. The Bunodonta — containing the families of the Hippopo- 

 tamidce and the Suidce. 



Both these divisions are very well characterized by their dentition. 



1 Part I. of this Catalogue— containing the Orders Primates, Cheiroptera, Insecti- 

 vora, Carnivora, and Rodentia — was noticed in the Geol. Mag. 1886, Decade III. 

 Vol. II. p. 321. 



2 See Prof. Flower's Article "Mammalia," Encyclop. Britannica, 9th. edit. vol. xv. 



