NEW MALLOPHAGA. 



455 



plane almost perpendicular to it, but inclined very slightly 

 forward; their tips meet in the middle line, so that they 

 form an arch over or ventral to the mouth-opening. The 

 anterior lateral projections of the submentum extend for- 

 ward beyond the bases of the mandibles, and the glossae 

 and paraglossae lie just back of their posterior margins. 

 Hence the mentum, ligula and mandibles are all enclosed 

 in the anterior semicircular border of the submentum. 



The right mandible is triangular in dorsoventral 

 section. The ventral part is thickened and prolonged 

 inwardly at the inner ventral angle, forming two large 

 thick, bluntly pointed teeth. These are separated from 

 each other only by a slight emargination, and they lie one 

 anterior to the other. The anterior of these probably cor- 

 responds with the dorsal tooth of the mandible oiAucistro- 

 nagigas; if so, it has changed its position so that its tip is 

 as far forward as that of the posterior tooth, and these 

 two have become fused into a single process. The ante- 

 rior tooth, however, does not reach quite as far inwardly 

 as the posterior one, and is also a little dorsal to it. Both 

 of these positions correspond with those of the dorsal 

 tooth of Ancistrona gigas and Lcemobothrium. A large 

 thick process projects inwardly from the inner dorsal 

 angle. This very evidently corresponds with the ex- 

 tremely similar process from the posterior inner angle of 

 the right mandible of Ancistrona, and with the less similar 

 but certainly homologous process of Lcemobothrium. 

 This projection is the inner end of a posterior thickening 

 of the mandible which bears near the outer anode of the 

 base, on the posterior aspect, the articulating condyle. 

 This projects dorsally, and fits into a socket on the ventral 

 side of the head. On the anterior side of the mandible, 

 somewhat more ventral than the condyle, is the articula- 

 ting facet into which fits a condyle from the ventral surface 



