308 M. Anton Stuxberg on M^riopoda 



known, viz. the Mexican one. The Craspedosoma depluiiatunij 

 n. sp., as bearing the strongest resemblance to a typical PoIt/- 

 desmus, is unique, having no known ally in any part of 

 the earth. The Craspedosoma dxdiuricum, Gerstf., and the 

 C. cylindricum^ n. sp., may be regarded as representatives of 

 the European C. Eaiclinsii, Leach, their close resemblance in 

 form pointing to a near affinity of origin. The Folydesmus 

 davatipes^ n. sp., is a form of the subgenus Icosidesmus^ Humb. 

 & Saussure (distinguished by the strange conformation of the 

 legs), of which, as far as I know, only one species has been 

 described, viz. from New Zealand. If we except the Litho- 

 hius sibi'ricus, Gerstf. (which has been, considering the claims 

 of the present time, very imperfectly described, and probably 

 is a collective species), and the L. osfi'acorum, n. sp. (a Litho- 

 hms sensu strictiore*), the remaining Lithohii belong to that 

 division of the subgenus Arcliilithobius which is characterized 

 by four (never more) teeth on the coxal part of the second 

 pair of jaw-feet, and by usually 20-jointed antenna, and of 

 which the centre, to judge from the 119 species hitherto known 

 of the genus Lithohius in the wider sense, seems to be in the 

 north-east of Asia, though it has also some representatives in 

 Europe, and at least as many on the Californian coast. 



It is obvious from the foregoing remarks that the Siberian 

 Myriopoda have very little in common with those of Europe ; 

 and what there is leads us to suppose that Asia has been the 

 centre in which they originated. In order to acquire a true 

 knowledge of the geographical distribution of the species, it 

 makes a great difference whether we say that Asia has received 

 such and such forms from Europe, or that Europe has received 

 them from Asia. The Siberian Myriopod fauna is much too 

 independent, as it were, in its composition, to allow us to speak 

 of genuine European forms. It seems we shall come nearest 

 the truth by saying that Europe has borrowed from Asia the 

 Myriopods it has in common with Siberia. 



l. Lithohius ostiacorum^ n. sp. 



Lainiaa cephalica subcireularis, lateribus valde rotundatis, eadem 

 longitudine ac latitudine, infra marginem posticum impressionibus 

 duabus rotundate triangularibus evanidis, laevis, setis rigidis longis 

 sparse vestita ; antennae articulis 20, cylindraceis, longe setosis 

 compositse, dimidiam corporis longitudinem assequentes ; oculi 

 cllipsoidei, ocellis 9-10 in 3 series (1 + 3, 2, 3 v. 1 + 3, 3, 3) 



• Compare Stuxberg, " Genera et Species Lithobioidarum '' (CEfvers. 

 Kgl. Vet. Akad. n. s. Forbaudl., Srg. 32 (1875). no. 3), where (p. 8) the 

 six subgenera EulUhohhis, Xeolithobius, Lithohius, Pseudolithobius, Hemi- 

 hthohius, and Archilithobim are briefly characterized. 



