424 u. 1. POCOCK. 



ai-ea of last marked anteriorly on eacli side with an oblique, 

 shallow groove. 



Legs shortish, hairy, armed with a single inferior tibial 

 and tarsal spine. Claw with two basal spinules, one inferior 

 and one posterior. Posterior legs long and slender, about one 

 third the length of the body and head, longer than the 

 antennse, without spines, protarsal and tarsal segments sub- 

 equal, segments subcylindrical, tarsal and protarsal subequal ; 

 femur, patella and tibia progressively decreasing in length. 

 Trochanter of the thirteenth and fourteenth armed below 

 with a horny spike, which is shortest on that of the thirteenth 

 coxa of fifteenth similarly armed. 



The genito-anal sclerite is about half the length of the last 

 leg-bearing somite. When viewed from the dorsal or ventral 

 aspect its sides are seen to be convex, and to converge pos- 

 teriorly to a point. From the lateral aspect its upper edge, 

 which is compressed, is straight and horizontal ; its inferior 

 edge convex, the two meeting at an acute angle of about 45°. 



Part II. — SummaPwY op the Chief Characteristics op 

 Oraterostigmus, and a Comparison between this Genus 



AND other ChILOPODA. 



The structural peculiarities of this new Chilopod and the 

 complex nature of its relationship to the other existing types 

 of this class, which are only imperfectly manifested in the 

 above-given description, may be more fully emphasised and 

 revealed in a clearer light by a brief summary : firstly, of the 

 characters in which it particularly resembles each of the three 

 most nearly allied groups ; secondly, of those that it shares 

 with two of them to the exclusion of the third ; and lastly, of 

 those in which it differs from all. Adopting the terminology 

 I have elsewhere proposed, I shall speak of these groups as the 

 Lithobiomorpha, Scolopendromorpha, and Geophilomorpha, 

 leaving the explanation of the use of these names and the 

 rank assigned to them to be dealt with in a later part of this 

 essay. 



