Fresidenfs Address. 37S 



of divergence. The Lophogastrids seem to have reached 

 their limit, and the present forms are preserved through 

 having taken to deep water, while the Thysanopods have 

 for the most part become pelagic. Anaspides may be 

 looked upon as a Palceocaris-\ike form, which has been 

 preserved by taking to a fresh- water habitat, while all its 

 marine relatives perished in the more severe struggle for 

 existence which marine forms have to undergo. 



MEROSTOMATA. 



The most important additions to the knowledge of Scottish 

 Eurypterids since the publication of Woodward's " Mono- 

 graph on the Merostomata " by the Palsetographical Society, 

 has been made by Malcolm Laurie, who has described, in a 

 series of papers before the British Association and the Eoyal 

 Society of Edinburgh, between the years 1892 and 1899, the 

 collections made by the late Messrs Henderson, Hardie, and 

 himself from the Wenlock Rocks of the Gutterford Burn, in 

 the Pentland Hills.^ The collections of Messrs Henderson 

 and Hardie are now in the Museum of Science and Art, 

 Edinburgh. 



In his papers before the Royal Society of Edinburgh he 

 adds four new species to the genus Uuri/pterus, Dekay, three 

 species to Stylomcrus, Page, and makes a new species of 

 Slimonia, Page. He is compelled to make two new genera 

 to receive some more generalised forms. One of these, 

 Drepanopterits, comprising three species, combines characters 

 found in Stylonurus and Eurypteoms, and for one species 

 with very generalised characters he makes the genus Bembi- 

 cosoma. 



The deposit in which the above forms occur, as shown by 

 the evidence afforded by Graptolites, is of Wenlock age, and 

 consequently older than the Ludlow rocks of Lesmahagow, 

 from which most of the other described Scottish Silurian 

 Eurypterids have been obtained. The discovery of more 

 primitive forms, combining the characters of more than one 



^ Eep. Brit. Assoc, p. 729, 1892; Trans. Boy. Soe. Edin., vol. xxxviii. 

 part i. p. 151, 1893; Ibid., vol. xxxix. p. 575, 1890. 



