Prof. Owen on the Ruminant Quadrupeds. 63 



trochanters on the femur, in having the fore-part of the astragalus 

 equally divided, and in having the pattern of the grinding surface of 

 the molar teeth more or less synuiietrical. The horned species have 

 the horns in one ])air, or two pairs. All have the stomach more or less 

 complex, and the ctecum small and simple. In the Hog the gastric 

 complexity is least displayed; hut in the Peccari the stomach has three 

 compartments; and in the Ilij)|)opotamus it is still more complex. 

 But the most complex and peculiar form of stomach is that which 

 enahles the animal to " chew the cud," or submit the aliment to a 

 second mastication, characteristic of the large group of even-hoofed 

 TJuffulata, called ^' Ruminantia." 



These timid quadrupeds have many natural enemies ; and if they 

 had been compelled to submit each mouthful of grass to the full 

 extent of mastication which its digestion requires, before it was 

 swallowed, the grazing ruminant would have been exposed a Ion" 

 time in the open prairie or savannah, before it had filled its stomach. 

 Its chances of escaping a carnivorous enemy would have been in a 

 like degree diminished. But by the peculiar structure of the rumi- 

 nating stomach, the grass can be swallowed as quickly as it is cropped, 

 and be stowed away in a large accessory receptacle, called the " ru- 

 men," or first cavity of the stomach ; and this bag being filled, the 

 ruminant can retreat to the covert, and lie down in a safe hiding- 

 place to remasticate its food at leisure. 



The modifications of the dentition, oesophagus, and stomach, by 

 which the digestion in the Ruminantia is carried out, were described 

 and illustrated by diagrams. 



The speaker next treated of the various kinds of horns and antlers ; 

 the manner of growth, shedding, renewal, and annual modifications 

 of the deciduous horns, the peculiarities of the persistent horns, the 

 mechanism of the cloven foot, and the proA"ision for maintaining the 

 hoofs in a healthy condition, were pointed out. 



The following were the chief varieties of the ruminating stomach. 

 In the small Musk-deer (Tnnjulus) there are three cavities, with a 

 small intercommunication-canal between the second and last cavity ; 

 the "psalterium," or third cavity, in the normal ruminating stomach, 

 being absent. This cavity is likewise absent in the Camel-tribe, which 

 have the cells of the second cavity greatly enlarged, and have also 

 accessor}' groups of similar cells developed from the rumen, or first 

 cavity. These cells can contain several gallons of water. The rela- 

 tion of this modification, and of the hump or humps on the back, to 

 the peculiar geographical position of the Camel-tribe, was pointed out. 



The modifications of the ruminating stomach ; the discovery of ru- 

 dimental teeth in the embryo Itia/n?iautia, which teeth (upper incisors 

 and canines) have been sup})Osed to characterize the Pachyderms ; 

 the occurrence of another alleged pachydermal character, viz. the 

 divided metacarpus and metatarsus, in the fa-tus or young of all rumi- 

 nants, and its persistence in the existing Mnsrhus aquations, and in a 

 fossil species of Antelope ; the absence of cotyledons in the chorion of 

 the Camel-tribe, with the retention of some incisors as well as canines 

 in the upper jaw of that tribe ; the ascertained amount of visceral 

 and osteological conformity of the supposed circumscribed order 



