A Monograph of Scytonotus. 235 



From both genera the bi-hamate male genitalia, with the distal 

 joint articulated at base, are a diagnostic character, for the eighth 

 legs of the other genera are replaced by a single falcate structure. 

 Polydesmus and Brachydesmus are much more closely related to 

 each other than either is to Scytonotus. 



Porat seems to think that this genus is closely related if not 

 identical with Brachydesmus, because of the 19 segments, but 

 this inference would seem unnecessary. It is evident, too, that 

 he takes an expansive view of generic limitations, necessary to 

 include his species Scytonotus digitatus, mentioned again below. 

 Wood had already recorded in his Monograph that the present 

 species has but 19 segments, with no pores on the last two. He 

 also pointed out the fact that the distal joint of the male genitalia 

 is articulated at base, but all European writers seem to have 

 ignored these observations. 



Notwithstanding the fact that several species from ditferent 

 parts of the world have been referred by their authors to Scyton- 

 otus, it seems probable that the genus as here described is mono- 

 typic, or at least conlined to Northeastern North America. 

 Reasons for this view may be stated briefly' in detail as follows : 



Scytonotus laevicollis C L. Koch. 



System der Myriapoden, p. 131. 

 Die Myriapoden, II., p. 41, fig. 163. . 



This species seems to have been founded on an entirelv insig- 

 nificant difference, as the author himself admits. A large suite 

 of specimens from different localities shows that the roughness of 

 the first segment is subject to much variation, being usually less 

 in females (?) 



Scytonotus nodulosus C. K. Koch. 



System der Myriapoden, p. 131. 

 Die Myriapoden, II., p. 43, fig. 165 



According to the original description this species has 31 legs 

 in the male, a unique condition of things unless the genitalia are 

 enumerated. The diagram gives 20 segments, and the dorsal 

 sculpture (three rows of scale like elevations, the anterior and 



