President's Address. 369 



species of Undoceras, there are the siphuncles of at least four 

 different species of Piloceras} 



PHYLLOCARIDA. 



The study of Scottish Palaeozoic fossils of this group has 

 been actively pursued in recent years. In the years 1880 and 

 1882 I described three species of Phyllocarid Crustaceans from 

 the Lower Carboniferous rocks of Eskdale, Dumfriesshire, 

 and made the genus Acanthocaris to hold them. They are 

 nearly allied to Ceratiocaris, Salter, but they differ from it in 

 the great size of the segmented body compared with the 

 carapace, and in the diminutive lateral cercopods of the tail 

 apparatus.^ The chief systematic work, however, has been 

 done by Professor T. Rupert Jones and Dv Henry Wood- 

 ward. In a series of articles in the Geological Magazine, 

 extending from 1884 to 1892, and in their Reports to the 

 British Association from 1885 to 1895, they make free use 

 of Scottish material. Their work, however, is brought to a 

 focus in their Monograph published by the Palaeontographical 

 Society.^ In it they describe, from the Silurian rocks of 

 Scotland, two new species of Aptychopsis, three new species 

 of Ceratiocaris, and figure about ten already known species 

 of Ceratiocaris, two species of Discinocaris, and one of Pelto- 

 caris. They make a new genus Calyptocaris to contain the 

 Dithyrocaris striata of Woodward and Etheridge, jun., from 

 the Ludlow rocks of Carmichael Burn in Lanarkshire,* and 

 they figure six species of Dithyrocaris from the Carboniferous 

 rocks of Scotland. 



The number of genera and species of Phyllocarida re- 

 corded from Scottish Silurian rocks by the Geological Survey 

 is as follows : — Aptychopsis, nine species ; Calyptocaris, one 

 species; Caryocaris, one species; Ceratiocaris, ten species; 



1 Mem. Geol. Sur., "Summary of Progress for 1898," p. 55, 1899. 



2 Trans. Roy. Soc. Edin., vol. xxx. pp. 73, 512. 



^ "Mon. Brit. Palseo. Phyllop. (Phyllocarida)," PaloBontogr. Soc, part i., 

 188&; partii., 1892; partiii., 1898; partiv., 1899. 



^ Mem. Geol. Sur., Explan. Sheet 23, Scotland, Appendix, pp. 43, 57, 

 100,1873. 



