292 R. I. POCOOK. 



the dorsal surface, at all events, of the anterior half of the 

 body is uppermost. 



For those who hold that the terrestrial Arachnids are 

 descended from marine ancestors allied to Limulus and the 

 Eurypterida, and recognise genetic affinity instead of '' for- 

 tuitous coincidence " and " convergence " in the many deep- 

 seated structural resemblances between the two groups, these 

 archaic scorpions have, since their discovery, been vested 

 with a peculiar interest, largely in view of the possibility of 

 their supplying fresh evidence in support of this relationship. 

 Little in this direction was yielded by the memoir on the 

 Gotland scorpion; and Peach's description of the Scotch 

 specimen, although containing many important anatomical 

 observations, was by no means exhaustive, and the figure that 

 accompanied it not all that could be desired. Hence it has 

 "for many years been felt that a complete and properly illus- 

 trated account of this unique fossil would make a valuable 

 addition to zoological literature. 



In July of last year Prof. Ray Lankester wrote for the loan 

 of the specimen to the authorities of the Kilmarnock Museum, 

 where it has been preserved since the death of Dr. Hunter. 

 The authorities not only kindly and promptly acceded to the 

 request, but most generously permitted the specimen to be 

 kept for three months at the Natural History Museum. I 

 gladly avail myself of this opportunity to express my sincere 

 thanks to Professor Lankester for placing the specimen in 

 my hands for investigation. I am also indebted to Miss G. 

 M. Woodward for the trouble and time she devoted to the 

 lithograph, her skill and experience in interpreting fossils 

 being most helpful in the present instance. 



2. Description of the vSpecimen. 



So far as the disposition of the various members is con- 

 cerned, my restoration agrees with that of Mr. Peach in most 

 particulars. I think, however, that the second leg on the 

 right side lies distally across the anterior portion of the 



