CHILOPODA. 133 
CHILOPODA, DIPLOPODA, AND PROTOTRACHEATA. 
By R. I. Pococg, F.R.S. 
The Chilopoda and Diplopoda were in existence in the Carboniferous Period in 
Europe and North America. But since these ancient forms were different from their 
modern representatives, and since they afford no help to an understanding of the 
present distribution of these classes, it is needless to discuss them further, and useless 
to repeat what has already been said on this head in the introduction to the essay on 
the Arachnida. 
Class CHILOPODA (Centipedes). 
From the geographical standpoint the Chilopoda or Centipedes are remarkable for 
the wide distribution of the orders and of most of the families into which the class is 
divisible. It is probable, however, that when the group has been studied in greater 
detail, the number of families, especially of the Geophilomorpha, will be considerably 
increased and their distribution better understood. The recorded Central American 
genera of Geophilomorpha and of Scutigeromorpha call for no special comment in the 
present connection, since they exhibit no special features throwing light upon the 
origin of the fauna of that country. The Lithobiomorpha and Scolopendromorpha are 
more interesting. 
The Central American species of the former order belong to the family Lithobiide, 
which, although of wide distribution with a few outlying species of the genus Lithobius 
in the Southern Hemisphere (India, Australia), is mainly northern, being spread all 
over Europe, Central Asia, and North America, and represented by a vast number of 
species in these continents. Hence it seems that the Central American representatives 
spreading through Mexico to Guatemala must be regarded as a northern element in 
the fauna of our area. 
The classification of the Scolopendromorpha proposed in my report may be revised 
as follows :— 
Family Cryproripa*. 
Subfamily Cryptopine (Cryptops +, Theatops, Otocryptops, Scolopocryptops). 
Subfamily Newportiinz (Newportia, Scolopendrides). 
Family ScoLopenpRiIp& (Cupipes t, Rhombocephalus, Scolopendra, Parotostigmus, Rhysida f). 
# Brélemann’s examination of the type of Scolopendropsis, showing that the genus is closely related to 
Pithopus, proves that the presence of 23 pairs of legs cannot be regarded as a character upon which a group 
of family rank can be based. I therefore follow Kraepelin in associating Otocryptops and Scolopocryptops 
with Cryptops. 
+ Added by Kraepelin to the Central-American fauna since my report was written. 
+ In Kraepelin’s Monograph of the Scolopendride (Jahrb. Hamb. Wissen. Arch. xx. 1903, p. 139), this 
genus, as expanded by that author, should have been named Trematoptychus, which antedates Rhysida by 
one year. 
