210 



Annelida GJwetapoda 



Elytra numerous, completely covering the body, or leav- 

 ing a naked median space of variable width; along the 

 posterior part of the body not always in pairs. Setae of 

 dorsal ramus, few, delicate : of the ventral ramus for the 

 most part bidentate, but with a few, stouter than the others, 

 pointed. 



This genus is closely related to Halosydna Kyihg. but 

 differs in the number and arrangement of the elytra, in 

 having pointed setse in the lower ramus, and in having a 

 distinct facial tubercle. In many respects it agrees with 

 Lepid ASTHENIA Mgru., but is excluded from that genus by 

 having setae in the dorsal rami. 



LePIDAMETRIA COMMENSALIS 71. sp. 

 PL. Ill, FIGS. 23-31, 



Head (f. 23), convex, sides rounded, widest and highest 

 at posterior third, posterior margin slightly concave. 



Eyes circular, black, lateral, all small, and in alcoholic 

 specimens seen with difficulty. Anterior pair largest, 

 situated at the widest part of the head. Posterior pair 

 mere specks, half way between the front pair and the 

 hind margin of the head. 



Lateral antennae, bases forming about one-third the 

 length of the entire head ; antennae a little longer than the 

 head. Base of median antenna stout, cylindrical, project- 

 ing a little beyond the origin of the lateral antennae. 

 Middle antenna one-third longer than the lateral. All the 

 antennae, together with the tentacular cirri and dorsal 

 cirri are cylindrical to near the end, where there is a very 

 slight swelling, after which they taper rapidly, having a 

 filiform termination. 



Palpi, stout, extending beyond the middle antenna, 

 decreasing regularly to near the end, where they become 

 suddenly filiform ; covered with minute cylindrical papillae. 



