Jheringula paulensie, a new generic Type of Macrothricidæ. 11 



of the body. It is generally extended behind, along the sides of 

 the body, and is not ciliated like the others, but armed along 

 the lower convex edge with small spinules. The 4 other 

 setae are distinctly biarticulate and, excepting the lowermost 

 of the 3 apical setæ, have a small spinule at the end of 

 the proximal joint. The upper ramus is 4-articulate, with 

 the 1st joint very small and simple, the other 3 differing little 

 in size. It carries only 4 setæ, the antepenultimate joint 

 having no such seta, but a small spine outside, similar to 

 that originating above the 3 apical setæ. In structure, the 

 setæ of this ramus exactly agree with those of the lower 

 ramus. Each antennæ is moved by the aid of 3 strong 

 muscles originating from the dorsal face of the cephalic 

 shield, and converging to the base of the stem. The two 

 posterior ones lie rather close together, extending straight 

 downwards from the hindmost part of the cephalic shield, 

 immediately in front of the cervical depression; the 3rd ori- 

 ginates farther in front, from about the middle of its length, 

 and passes obliquely backwards. This latter muscle represents 

 the protractor, the other 2 the retractor muscles of the an- 

 tennæ. All three are continued through the stem, and are 

 attached to its most distal part. 



The anterior lip, or labrum (see PI. II, fig. 2), forms the 

 immediate continuation of the lower compressed part of the 

 head, though movably connected with it at about the 

 point where the anterior edges of the valves pass into the 

 inferior ones on each side. It is produced below to a rather 

 large triangular projection pointing backwards, and terminates 

 in a rounded lamella, finely ciliated on the edge, and admit- 

 ting of being brought into immediate contact with the oral 

 parts. By the aid of 2 slender muscles joining its base 

 from each side, and passing from the dorsal face of the 



