The President's Address. By Dr. H. Woodward. 153 



shores of Scotland, Iceland, Faroe Islands, Greenland, and the shores 

 of Newfoundland, but since the year 1844 it has been completely 

 exterminated by man. 



Mammalia. — In the earlier groups of the Vertebrata which we 

 have already considered, the young have, as a rule, been deposited 

 by the parent enclosed in an egg, while in a few instances they 

 have been found to be hatched before birth, as in the case of the 

 Viper among Reptiles, the Blenny among Fishes, the Scorpion in 

 the Arachnida, the Flesh-Fly, and the Earthworm. Among Mam- 

 malia in general, the foetus is nourished by the parent before birth 

 by a vascular membrane called the placenta, in which it is en- 

 closed, and when born it has usually attained a certain amount of 

 growth ; in fact, the young are born alive, and are suckled by the 

 parent until sufficiently advanced to be able to feed themselves. 



Birds, we have seen, are clothed in feathers, but the Mammalia 

 have instead a hairy covering, which is seldom entirely absent 

 even in huge aquatic forms like the whales ; whilst a few large, 

 apparently-naked, terrestrial, tropical species possess hairs on certain 

 parts of the body : for instance, the Cetacea have short bristles at 

 least on the lip ; animals like the Elephant and the Hippopotamus 

 have some hairs, whilst the extinct Mammoth had a complete hairy 

 and woolly covering. Mammals, chen, may be described as warm- 

 blooded, hairy animals, the head being attached to the vertebral 

 ■column by a double-occipital condyle. They are viviparous (bring- 

 ing forth their young alive), and the young are suckled by a 

 secretion, known as milk, furnished by the mammary glands. 



The earliest mammals known belong to the Prototheria. 



Prototheria : Multituberculata. — Two living examples of 

 the Monotremata {Ornithorhynchus and Echidna), small, toothless, 

 burrowing animals, probably represent the sole survivors of the 

 first-known mammals of the Trias, the Stonesfield Slate, and the 

 Purbeck Beds. 



There is a remarkable resemblance between the early-shed teeth 

 of the immature Ornithorhynchus and the multituberculate molars 

 in certain small jaws found in Mesozqic and Eocene strata. 



Some of the forms originally placed by Owen among the earliest 

 mammals, as, for instance, Tritylodon, from the Trias of South 

 Africa, are now referred to the Anomodont Pteptiles, with Cyno- 

 gnathus, etc. Those still considered to represent early mammals are 

 placed in the Multituberculata, on account of the number of 

 tubercles borne on the molar teeth ; the most interesting of these 

 are Amphilestcs, Phascolotherium, and Stereognathus, from the Great 

 Oolite Stonesfield, and Plagiaulax, Microlcstcs, Bolodon, Allodon, 

 Ctenacodon, from the Purbeck Beds — all these represent extremely 

 small animals, not bigger than a rat or a mouse. Polymastodon is 

 represented by somewhat larger animals, one being equal in size 

 to a kangaroo ; the teeth are on the rodent pattern, with cutting 



April 20th, 1904 M 



