BRITISH SPECIES OF THE ORDER SYMPHYLA 647 



order more deeply. Towards the end is an account of all 

 European species recognised by Hansen with the localities he 

 gives for them. 



My thanks are due to my friends Prof. G. H. Carpenter and 

 Dr. Randell Jackson for the material they kindly submitted to 

 me. 



Order SYMPHYLA. 



Scutigerella iit'vea (Scop.) is the first described species of 

 the order, being described by Scopoli as a Scolopendra in 

 1763. Then in 1839 Gervais described Scolopendrella nota- 

 cantha founding the genus Scolopendrella, whilst six years later 

 Newport found the commonest known form, S. inunaculata. 

 It was not until 1880, however, that the group was raised to 

 the rank of a separate order, Symphyla, by Ryder, who 

 characterised the two genera now recognised by biologists. 



Genus SCUTIGERELLA, Ryder, 1882*. 



The species of this genus are as a rule larger, have the first 

 pair of legs well-developed and more than half the length of 

 the following pair, and the exopodsf well-developed and 

 decidedly conspicuous, rarely very short. 



The posterior margin of all the dorsal scuta but the last 

 one are slightly rounded or emarginate, with angles often 

 broadly rounded, rarely angular, but when angular each lobe 

 is several times broader than long. The front surface of the 

 hind pair of legs is covered with numerous setag, whilst the 

 cerci are simple, that is, without the striped terminal area or 

 the transverse lines seen in the cerci of Scolopendrella. 



Scutigerella immaculata, Newport, 1845. (PI. xix., 

 figs. I, 5-6)- 

 A large and variable though very distinct species, some- 

 times measuring close upon 8-o mm. in length, it comes in 

 Hansen's first group of the genus, chiefly recognised by the 



• Proc. U.S. Xat. Mus., v., p. 234, 1882. 



t The esopods are the protruding- retractile organs found at the base of each 

 leg of the ten posterior pairs. 



