REPORT ON THE AMPHIPODA. 1303 



Epistome prominent, helmet-shaped. 



Upper Lip not quite symmetrically bilobed, the emargination between the two lobes 

 being very deep. 



Mandibles.— The cutting edge sharp, oblique, more than two-thirds of the breadth of 

 the trunk, the upper angle produced into a tooth ; this tooth on one mandible crosses its 

 fellow on the other just above the emargination of the upper lip, under which the cutting 

 edges of the mandibles lie, except at their lower extremities ; there is a small tooth on the 

 lower margin a little to the rear of the cutting edge, and to the rear of this tooth there is 

 a row of short spinules and setules ; the left mandible has a small tooth-like secondary plate 

 high up on the inner surface ; each mandible has on the inner surface a curved diagonal 

 brush of numerous setae extending from the lower front angle to near the base of the 

 palp ; the palp is set very far back, the first joint short, a little longer than broad, the 

 second joint long, apically a little widened, with setae along one margin and many about 

 the distal end, the third joint shorter than the second, apically pointed, one margin 

 convex, smooth, the other sinuous, furred with cilia. 



Lower Lip. — PL CLII. shows the two mandibles from the inner side, clipped above 

 by the transversely oval inner plate of the upper lip, and supported below near the outer 

 corners by the mandibular processes of the lower lip. The figure of the mouth organs in 

 PI. CLI. shows the two mandibles from the outer side clipped above by the outer plate 

 of the upper lip, but the lower lip is concealed by the maxdlaa. 



First Maxillse. — The inner plate broad, with sinuous distal margin, both that and 

 the surface carrying very numerous spinules ; the outer plate not so broad as the inner, 

 reaching beyond it, with many spinules, especially on and near the inner margin, the 

 somewhat narrowed apex carrying on the inner side a rather slender spine followed 

 closely by a very stout one, with another equally stout but shorter below it on the outer 

 side, and somewhat further down a stout curved spine, followed by another planted on 

 the surface just within the outer margin ; there are also a few small spines on the trunk 

 of the joint to which this plate belongs ; the palp rather longer than the outer plate, 

 near the middle of the base of which it is attached by a ridge of its inner surface, this 

 attachment causing both the margins of the palp to face inwards ; that which appears 

 to be the true inner margin has several distant short spine-teeth spaced along it; between 

 that at the almost acute apex and the next below it there is a marked emargination ; on 

 the outer slope of the apex there is a feathered spine ; the outer margin is convex, 

 pectinate with Little spine-teeth for more than half its length from the apex. 



Second Maxillse. — The inner plate shorter but broader than the outer, with 

 thirteen spines of various lengths planted on and just within the serrate distal margin, 

 the outer and inner margins and one surface having cilia or spinules on the distal 

 portion ; the outer plate has eight spines on the truncate oblique apex, the outer and 

 inner margins and one surface armed as in the other plate. 



