102 



PROCEEDINGS OF THE NATIONAL MUSEUM 



in going upward. The extreme lateral ends may be turned outward, 

 as for instance in Scohinomus, and are readily visible from above. 



Body segments: A close scrutiny of the body segments in our 

 material has revealed some interesting information of a broad mor- 

 phological nature. It seems pertinent to preface a consideration of 

 segmental sculpture with some remarks on the composition of seg- 

 ments in the Spirobolida. 



For many years the segments of spiroboloid millipeds were generally 

 considered to be composed of a sternite and a completely coalesced 



Figure 1. — Structural details of Eurelus soleatus: a, Gnathochilarium; t, hypopharynx; 

 c, semidiagrammatic sketch of a midbody segment showing the two fused sternites, and 

 the pleurite and lower tergal elements of the left side. Abbreviations; PL, pleurite: 

 PZ, prozonite; MSZ, mesozonite; MTZ, metazonite; ST 1, anterior sternite; ST 2, pos- 

 terior sternite. 



"pleurotergite" often divided by a transverse suture into a prozonite 

 and a metazonite, the latter occasionally with a faintly defined longi- 

 tudinal suture behind the ozopore. In numerous publications by 

 two such celebrated authorities as Attems and Verhoeff, suprageneric 

 groupings were often based on the location of the pore in front of or 

 behind the transverse suture. That the traditional dichotomy of 

 "prozonite" and "metazonite" is untenable was first established by 

 Cook (1896), who discovered that the spiroboloid segment is composed 

 of a double sternite, a distinct pleurite on each side, and a dorsal 



