714 PROCEEDINGS OF THE NATIONAL MUSEUM. 



subequal, the fourth slightly longer than the third or fifth, sixth only 

 slightly shorter than fifth; olfactory cones four. 



First segment three times as long as broad, posterior margin dis- 

 tinctly curved forward, so that the segment is laterally much shorter 

 than in the middle. Segments dorsally even and smooth, neither gran- 

 ular nor areate. 



Lateral carina? with thickened margins distinct, twice as broad on 

 poriferous segments, distinctly narrower on i)osterior segments than on 

 anterior; margins not expanded, not broader on segments 1 to 4 than on 

 segment 6; posterior corners of carinte slightly produced, increasing 

 caudad from the fifth segment ; anterior and posterior edges of carinse 

 very narrowly or faintly margined. 



Eepnguatorial pores 13, located in shallow cavities. 



Preanal scale minutely apiculate, the setiferous tubercles distinct, 

 close to the apex but not exceeding it. 



Sterna with a distinct, transverse, medianly interrupted ridge be- 

 tween bases of each pair of legs. 



Sternum of sixth segment of male with an oblong, minutely apiculate 

 process between the bases of the anterior pair of legs. 



Sternum of fifteenth segment of male with a broadly triangular 

 ensiform process projecting cephalad between the anterior pair of legs. 



Legs of male moderately crassate, dorsal face of second joint inflated, 

 anterior six male legs with a small fleshy apical sole, the claw reduced. 



Second male legs with coxa? moderately produced into a blunt cone. 



Copulatory legs as described for Omodesmus, but the two spines 

 described in Omodesmus are subequal and there is another smaller 

 spur located at the base of the mesial spine and directed mesad; the 

 flagellum is bent laterad beyond the lateral spine, and makes nearly 

 two turns in a difluse spiral ; its apex lies between the bases of the 

 copulatory legs and not upon the nodus as in Astrodesmus. 



The sixth aiitennal joint is distinctly longer in proportion to the 

 fifth than in Astrodesmus, and the autenn.e as a whole, as well as the 

 individual joints, are somewhat more slender than in that genus. 



Repugnatorial pores appear much smaller in this genus than in Astro- 

 desmtis, where they are located in large cavities. 



The process of the fifteenth segment is accommodated by a depres- 

 sion very slight in comparison with that of Astrodesmus. 



As remarked under Omodesmus, there is great similarity between the 

 copulatory legs of it and Aulodesmus, while those of Astrodesmus, though 

 constructed on the same plan, offer several differences from both. The 

 mesial and lateral spines are almost rudimentary in Aulodesmus, the 

 flagellum, though it rises similarly from the anterior (by flexure poste- 

 rior) face of the node, does not coil spirally, but is bent back upon itself 

 and then turns mesad so that its bidentate apex lies against the node 

 of its fellow. A small sinne, perhaps homologous with the sjiur-like 

 process described for Omodesmus, arises in Aulodesmus from the proximal 



