202 



BULLETIN 93, UNITED STATES NATIONAL MUSEUM. 



on the ciiticiilar ridges along the sciital border, but none on the 

 outer surface of the plate. Internall}^ the upper or beak portion 

 of the plate is transversely striated. The articular ridge is high and 

 massive, arcuate ; the articular furrow wide but not very deep. The 

 crests for the depressor muscle are short and sharp. 



Mandible (fig. 64&) has four principal teeth. The upper two 

 are rather long and acute, the second one in the middle of the 

 edge. The third and fourth teeth are blunt, and there are two 

 denticles between them. The lower point is short and slightly 

 bifid. The lower edge of the mandible is heavily bearded. The 

 two mandibles are exactly similar. 



Maxilla (fig. 64<?) has an even edge except for a notch below 

 the upper two large spines. There are six or seven large spines, 



Fig. C>4. BALANLIS HOEKIANUH, TiPE. a, CIRRUS I. b, MANDIBLE. C, MAXILLA. (/.SEGMENTS 



OF CIRRUS VI. 



two near the lower angle being longer, and a few smaller ones 

 below the notch. A band along the edge of the maxilla and below 

 the lower angle is bristly, and there are a few hairs along the upper 

 edge. 



The first cirrus has rami of 9 and 13 segments, the anterior ramus 

 two-thirds as long as the posterior. The segments are rather densely 

 hairy and spinose, and in the terminal tuft of the shorter segment 

 there are some bipinnate spines (fig. 64a). Cirrus ii has rami of 

 10 and 9 segments, the anterior longer by three segments. The seg- 

 ments have the usual bands of spinules on the distal part, widening 

 toward the anterior side. 



Cirrus iii has 14 and 13 segments, the anterior ramus longer by 

 five segments. Spines as in cirrus ii. 



Cirri iv to vi are longer, with segments bearing two large and one 

 small pair of spines, and some short spines on the anterior edge, be- 

 tween the j)airs (fig. Q-Ld). 



