54 University of Michigan 



Antennae inserted not far apart, the distance between their 

 sockets but Httle greater than the diameter of the latter. Head 

 depressed or widely furrowed from base of each antenna cau- 

 dolaterad, the proximal portion of antenna lying in this fur- 

 row. \^ertigial sulcus distinct to level of antennae. Setae 

 over entire surface of head numerous and nearly uniformly 

 distributed. 



Colkim but little narrower than head inclusive of cardines. 

 Anterior margin convex, continuing evenly about the rounded 

 anterior corners into the sides. Posterior angles subrectangu- 

 lar. Lateral margin in front of posterior corner with two or 

 three weak and wide crenulations. Entire dorsal surface 

 densely granular, but with no large tubercles. A little behind 

 the anterior border along edge of the darker area a transverse 

 row of four widely separated setae. (PI. 20, Fig. 136.) 



Second tergite a little wider than the collum, its keels bent 

 forward, decidedly longer than median portion of tergite, the 

 lateral margin of each with an acute tooth at anterior corner 

 followed by two crenulations, the posterior corner being a little 

 acute and distally rounded. (See PI. 20, Fig. 136.) The 

 third tergite similar to second, but median region a little 

 longer actually and relatively to the keels. Fourth tergite with 

 keels less bent forward and length of median region obviously 

 greater relatively and actually, the four marginal teeth of 

 keels the same. Each keel of the fifth tergite has an anterior 

 laterally bidentate portion separated by a cleft from an equally 

 long projection bearing the pore in its lateral margin, this 

 prominence smooth excepting for a few slight granules. The 

 other poriferous keels are similar, excepting that three teeth 

 are normally evident on anterior lobe. The non-poriferous 

 keels have four marginal teeth, these less rounded, more serri- 

 form than in anterior segments, witli the posterior angle 



