lO© PROCEEDINGS OP THE GEOLOGICAL SOCIETY. 



marks on the scar are marks of leaves or marks of bundles. Pro- 

 bably these sears are found in different genera, but the scars may 

 be of as great importance as the leaf-scars themselves for grouping 

 the plants in genera. He thought the cushions and permanent 

 leaf-bases, as in some living Cycads and Lycopods, were parts of 

 the leaf, not parts of the stem. 



Prof, EoxD Dawkins said that he had a large collection of Coal- 

 plants under his charge in the Manchester Museum, including forms 

 similar to those exhibited by the Author. This collection throws 

 much light upon Lepidodendroid plants, and he agreed with the 

 Author as to the propriety of classing together the various forms of 

 Lejpidodendra and Sigillarioe. Prof. Williamson regarded all the 

 species named as merely forms of Lepidodendroid plants. He was 

 inclined to regard the Ulodendroid scars as impressions of seed- 

 cones, and not of aerial roots, because on the best specimens of 

 these scars there are impressions of whorls of leaves or modified 

 leaves. In these plants the bark consists of several layers ; hence 

 arise the various patterns exhibited, which have led to the estab- 

 lishment of different genera. 



Prof. Seelet said that in former years he had worked through 

 some collections of Coal-plants. If Ulodendron were a good genus, 

 then the internal difference of structure between SigiUaria and Le- 

 pidodendron could not be general. The character of Ulodendron is 

 apparently of not less value morphologically than the form of the 

 leaf-scar. And, whatever the Ulodendron structure implied, Ulo- 

 dendroid scars had been described by M'Coy in a slightly modified 

 SigiUarian trunk, running round the stem instead of vertically. 

 M'Coy thought that they were the places of attachment of rootlets. 

 The phenomena seemed to be in favour of the development of fruit- 

 organs, and not of roots from the Ulodendroid scars. 



The Atjthoe, in reply, remarked on the generic distinctions be- 

 tween the leaf-scars of Lepidodendron and SigiUaria. The constancy 

 of leaf-scars throughout the plants shows that there are real generic 

 distinctions between them. Some of the specimens exhibited 

 showed the mode of attachment of the appendicular organ, and 

 these could not be scars of appendicular roots, because they contain 

 markings due apparently to leaves. The particular specimen on 

 which Mr. Carruthers mainly founded his notion of aerial roots was 

 not, in the Author's opinion, Ulodendroid at aU. The genus Arthro- 

 pilus ?, described by M'Coy, was founded on a badly preserved com- 

 pressed stem. 



2. " On an almost perfect Skeleton of Bhytina gigas = Bhytina 

 >SfeZZeW('Steller's Sea-cow') obtained by Mr. Eobert Damon, F.G.S., 

 from the Pleistocene Peat-deposits on Behring's Island." By 

 Henry Woodward, LL.D., F.E.S., F.G.S. 



The following specimens were exhibited : — 



Eecent skulls of male and female Dugong {Hdlicore australis) and 



