REPORT ON THE AMPHIPODA. 831 



upturned ; the fourth has u transverse dorsal dejaressiou and a cilium near the end of 

 the convex part which follows the depression. 



Eyes small, round, dark, with about twenty-five rather long ocelli. 



Upper Antennae subequal in length to the lower, the peduncles being shorter but the 

 flagella longer, first joint of the peduncle short, embedded in the head ; the second much 

 longer than the first or third, with some deep serrations on the lower margin, and various 

 groups of strong spines on the surface and margins ; the third joint not much longer 

 than the first of the flagellum, with one large group of spines near the base ; the flagellum 

 of six joints, of which the first is the longest ; the secondary flagellum of three, of which 

 the first is nearly as long as the first of the primary, but more slender, the third is 

 minute. 



Lower Antennw. — These are separated by a wide interval from the upper antennae, 

 and in the natural position of the head may be described rather as being set behind than 

 below the other pair ; the basal part of the first and second joints somewhat expanded, the 

 gland-cone small but distinct; the third small, scarcely reaching beyond the gland-cone 

 at its side, the fourth and fifth long, armed on the margins with spines and long setse, the 

 fifth joint shorter than the fourth, but longer than the slender three-jointed flagellum, 

 which is outstripped by the apical setee of the fifth joint. 



Upper Lip. — Distal margin rounded, but with the centre flattened and a little 

 roughened with projecting points. 



Mandibles. — Cutting plate with a small apical margin showing one or two little 

 denticles, seemingly folded over a small secondary plate, the part of the mandible in 

 front of the palp and molar tubercle forming a long bent tongue or tooth, without, so far 

 as could be perceived, any spine-row ; molar tubercle prominent, with small denticles ; the 

 slender palp set just over the molar tubercle, the first joint short, the second curved, with 

 the front margin convex, the third straight, nearly as long as the second, tipped with 

 four or five short setae. Whether a secondary plate belongs to either, both, or neither of 

 the mandibles I have not been able to determine. 



Lower Lip of delicate structure, principal lobes broadly rounded, little dehiscent. 



First Maxilla}. — Inner plates small, slender, not very distinctly made out ; outer 

 plates broad, with eight or nine spines on the apical border, the innermost straight, 

 pointing away from the rest, the remainder more or less curved, some with a single lateral 

 tooth, the outermost simple, broad-tipj^ed ; the palp one-jointed, slender, not reaching so 

 far as the outer plate, ti^jped with three setse, two of which are long, reaching beyond 

 the spines of the outer plate. 



Second Maxilhe. — The inner plate broad at the base, round the apical and upper part 

 of the inner margin carrying several setae ; the outer plate very much broader than the 

 inner, the broad oblique apical margin carrying numerous set« or seta-like spines ; there 

 is a single cilium near the apex on the convex outer margin. 



