LIBRARY 



YIII.— ^ Monograph of Sci/tonotiis. NEW YORK 



.. iOTANfCA! 

 BY O. F. COOK AND A. C. COOK. •!.>;.^rK ■ 



Read March 26, 1894. 



As is the case with nearl}^ all the extra-European genera of Di- 

 plopoda, and especially with the American, the more important 

 characters of Scvtonotus have been misunderstood or entirely 

 overlooked. This is evidenced by the fact that all the European 

 writers who have touched upon the subject have either made 

 dii'ect misstatements concerning the characters and affinities of 

 the genus, or have referred to it species having scarceh^ an^^ im- 

 portant features in common with the typical form. 



The genus is furthermore interesting in that its secondar}-- 

 sexual characters show it to be the most specialized of the Poly- 

 desmidf^ — characters which seem to be entirel}' unmentioned in 

 the literature of the subject. 



Genus SCYTOIVOTUS C. L. Koch. 



Systems der Myriapoden. 



Segments 19, covered with setiferous granules ; supplementary 

 margin pectinate; repugnatorial pores on smooth, rounded eleva-- 

 tions of segments 5, 7, 9, 10, 12, 13, 15, 16, 17 ; male genitalia bi- 

 hamate. 



Body small, 5-6 times as long as broad ; cavity slightly depressed. 



Antennae moderately clavate, third joint as long as the two preceding 

 joints taken together, joints in order of length : 8, 6, 5, 4, 2, 1, 7. 



Mandibulary stipe with exposed snrface divided by sutures into six 

 areas, five triangular, one trapezoidal. 



Masticatory plate long triangular, with numerous (15-20) transverse 

 ridges. 



Annals N. Y. Acad. Sci., VIII, Nov., 1894.— 17 



