Millipeds of Genus Brevigonus 57 



Holotype.— Length 49.6 mm, maximum width 11.5 mm, W/L ratio 

 23.2%, depth/ width ratio 62.2%. Segmental widths (in mm) as follows: 



collum 7.8 10th-13th 11.5 



2nd 8.9 14th 11.3 



3rd 10.1 15th 11.0 



4th 10.4 16th 10.6 



5th 11.0 17th 9.4 



6th-9th 11.4 18th 6.9 



Color in life: paranota bright red, color indented slightly mediad 

 along caudal edges; metaterga and collum glossy black, without stripes. 



Somatic features similar to shelfordi (see Shelley 1980), with fol- 

 lowing exceptions: Width across genal apices 5.2 mm, interantennal 

 isthmus broad, 1.8 mm. Antennae moderately long and slender, reach- 

 ing back to caudal edge of 3rd paranota, relative lengths of antenno- 

 meres 2>3>4 = 5>6>1>7. Facial setae as follows: epicranial, interan- 

 tennal, frontal, and genal absent, clypeal about 10-10, labral about 

 14-14. 



Dorsum very glossy, slightly coriaceous on anterior portions of 

 paranota. Latter moderately depressed, subcontinuous with slope of 

 dorsum. Collum very broad, extending well beyond ends of following 

 tergite. Caudolateral corners of paranota rounded through segment 7, 

 becoming blunt and progressively more acute thereafter. 



Process of 4th sternum (Fig. 1) enormous, much longer than widths 

 of adjacent coxae; processes of 5th sternum large, knobs between 4th 

 legs subequal to widths of adjacent coxae, flattened areas between 5th 

 legs produced into knobs, shorter than widths of adjacent coxae; ster- 

 num of segment 6 slightly elevated into two small lobes between 6th 

 legs, convexly recessed between 7th legs to accommodate curvatures of 

 acropodites, 7th legs set slightly farther apart than 6th. Postgonopodal 

 sterna bilobed on segments 8-10, with thick patches of stiff setae on 

 lobes, becoming flattened with varying shallow grooves and impressions 

 and fewer setae posteriorly. Coxae with low tubercles beginning on 

 segment 10, becoming spine-like on 14 and continuing posteriorly. 



Gonopodal aperture elliptical, 4.1 mm wide and 2.2 mm long at 

 midpoint, strongly indented on anteriolateral edges, sides thickened and 

 elevated above metazonal surface. Gonopods in situ (Fig. 2, of para- 

 type) with acropodites in subparallel arrangement, extending forward 

 over anterior edge of aperture between 7th legs, not overlapping or 

 touching. Gonopod structure as follows (Fig. 3-4): prefemoral process 

 absent, with elevated setose ridge at location of process but without 

 sclerotized projection. Acropodite moderately thick and heavy, curving 

 distally into broad arch, flattened at peak, overhanging and extending 

 well beyond level of prefemur; basal zone with large, caudally directed 



