Chilopoda , 17 h 



dd Ventral pores present, these arranged in four areas. 



Nesidiphilus Chamberlin. 



cc No clypeal area present. (Distoectal angle of coxee of second maxillae prolonged.) 



d No ventral pores present; distoectal angle of tibia of second maxillae prolonged 



and strongly ehitinized. Brachygonarea Ribaut. 



dd Ventral pores present; distoectal angle of tibia of second maxiUae not thus 

 prolonged, 

 e Lappets present on first maxiUae. Polygonarea Attems. 



ee No lappets present on first maxillae. Rihautia Brolemann. 



Cryophilus, n. gen. 



Frontal suture absent or very vaguely indicated. Prebasal plate not 

 exposed, the cephalic overlapping the basal. Dorsal plates bisulcate. 



Antennae short, filiform. 



Clypeal area present, finely aerolated. 



Labrhm free, tripartite. Median piece distinct and of good size but com- 

 pletely overlapped and covered from below by the lateral pieces which are in 

 contact at thfe median line. Lateral pieces fronged throughout with numerous, 

 closely arranged, long spinescent processes^ 



Outer branch of first maxillae distinctly biarticulate; bearing two mem- 

 branous lappets of which the distal one is the larger in the genotype. Inner 

 branch undivided, set off by a suture. Coxse completely coalesced. Coxae 

 of second maxillae weakly united at middle by a less chitinous isthmus; pleuro- 

 sternal sutures strongly developed; pore mesad of anterior part of suture, opening 

 through mesal edge of sclerite; palpus triarticulate, terminating in a large 

 simple claw, none of the joints with processes. 



Prehensors large, exposed at the sides and projecting well beyond the front 

 margin of the head. Claw armed at base; femuroid also armed and the inter- 

 mediate joints with weaker teeth. 



Prosternum without chitinous lines. Anterior margin unarmed. 



No ventral pores present. 



Spiracles circular. 



Last ventral plate of intermediate width, sides converging caudad, trapezi- 

 form. Tergite of last pediferous segment very broad, moderately narrowed 

 and rounded caudad. 



Coxopleurae moderately inflated, not unusually elongate or exposed at 

 sides of prescutum. Pores small and moderately numerous, mostly near edge 

 of ventral plate. 



Anal pores present, small. 



Anal legs clawless; consisting of six joints beyond coxopleurae. 



Genotype: C. alaskanus, n. sp. 



This genus is undoubtedly close to Arctogeophilus, established as a sub- 

 genus in Geophilus . by Attems,^ but now obviously distinct from the latter in 

 generic and in subfamily or family standing. , Attems' figure of the maxillae . 

 of the genotype of Arctogeophilus, A. glacialif, shows the palpi of the second 

 pair as quadriarticulate, a condition in which, if correctly represented, the 

 species is unique. Prof. Ribaut segregates the genus Gnathomerium from 

 Arctogeophilus on the assumption of the correctness of this figure.^ Aside 

 from this character, with the doubt one can scarcely help feeling as to the exact- 

 ness of Attems' figure, Cryophilus differs in the presence of distinct clypeal 

 area, which is definitely denied to Arctogeophilus by its author. Also, the 

 figure mentioned represents the segmental pore as enclosed on the mesal side, 



1 " Die Myriopoden der Vega Exped.", Arkiv for Zoologi, 1909, 5, p. 23. 

 2L0C. cit.; pi. 1, f. 2. 



3 " Sur un Genre Nouveau de la Sous-tribu des Ribautiina," Bull. Soc. d'Hist. hat. et de Sci. 

 biol. de Toulouse, 1910, 43, pp. 106, 106. 



