308 E. I. POCOCK. 



apparently less curved, less circular in section, and moi-e tri- 

 angular than in recent scorpions and the Swedish specimen, 



3. Description of the Species, with Notes on the othek 

 KNOWN Silurian Scorpions. 



The preceding description of the Scottish fossil, and the 

 comparisons that have been made between it and the Swedish 

 specimen, have revealed some noticeable structural differ- 

 ences between the two, which leave no other course open 

 than to regard the former as the representative of a distinct 

 and undescribed species. This I propose to dedicate to Dr. 

 Hunter, and to diagnose as follows : 



Palseophonus Hunteri, sp. n. 



Differing from P. nuncius in its much smaller size, being 

 35'5 mm. as compared with 62 mm. in total length, in 

 possessing a pair of median eyes set close to the anterior 

 border of the carapace, in having the digits of the chelicerge 

 longer and thinner, and the moveable more curved, and the 

 chelae very much lighter in build, with the digits nearly 

 straight ; in the absence of a spur from the fifth segment of 

 the first, second, and third pairs of legs, and in the smooth- 

 ness of the inferior median keels on the posterior segments 

 of the tail. 



In addition to the specimens discussed in the preceding 

 pages, two other scorpions have been recorded from Silurian 

 strata, namely, Proscorpius Osborni and Palaeophonus 

 loudonensis. The first was described by Whitfield 

 ('Science,' vi, p. 88, 1885; 'Bull. Amer. Mus. Nat. Hist.,' i. 

 No. 6, pp. 181 to 190, 1885), and was based upon a fairly 

 well preserved specimen, with the dorsal surface exposed, 

 from rocks referred to the middle of the Upper Silurian. 

 Like the Swedish and Scotch specimens, it was associated 

 with fossil remains of Pterygotus, Eurypterus, and other 

 marine organisms. 



The specimen was examined by both Whitfield and 



