REPORT ON THE AMFHIPODA. 981 



and lower antennse ; the first segment of the perseon the shortest, the seventh the longest ; 

 the pleon carinate, each of the first five segments dorsally produced backwards in a small 

 but pronounced tooth, with a cilium attached to the under side ; the first three segments 

 of the pleon long, the postero-lateral angles produced in a small sharp tooth, larger on 

 the third segment than on the others, and on that segment upturned ; the hind margin 

 of the third segment is sinuous on each side below the dorsal tooth. 



Eyes themselves not perceived, but from traces on the integument of the head it may 

 be inferred that they were present, and of considerable size. 



Upper Antennze. — First joint considerably longer than the two following united, 

 the second more than half the length of the first, with three groups of setae on the 

 inner side, distally produced into two sharp points, the third joint not longer than 

 broad ; the flagellum of thirteen joints, the first nearly twice as long as the third 

 joint of the peduncle, all together rather longer than the whole peduncle ; the secondary 

 flagellum of nine (on one antenna of eight), joints, equal in length to the first five of the 

 primary. 



Lower Antennse longer than the upper, the first joint little expanded, the second 

 more than usually distinct from the first, with a blunt inconspicuous gland-cone, the 

 third much longer than the second, with some small spines at the lower apex ; the fourth 

 joint more than twice as long as the third, with some spines along the margins, the fifth 

 rather longer, also set with spines or short setse ; the flagellum of thirteen joints, not 

 nearly so long as the peduncle. 



Upper Lip. — The distal plate somewhat of a transverse oval in shape, its distal margin 

 insinuate in a very slight almost imperceptible degree, furred in the usual manner. 

 (This description is given from the Heard Island specimen.) 



Mandibles. — The cutting edge angled, divided into six teeth, the four uppermost 

 being small, the next the most prominent, the lowest as large as this or larger; the 

 secondary plate of the left mandible is almost as large and powerful as the principal, its edge 

 less oblique, divided into five teeth, of which the lowest is the largest, the uppermost the 

 smallest, with two small denticles on its side ; on the right mandible the secondary plate 

 is much feebler, the edge denticulate with seven or eight little denticles and two mode- 

 rately strong teeth at the lowest part ; the spine-row consists of six spines, those nearest 

 the cutting edge being the strongest ; from the bluntness of these spines in actual use 

 compared with their sharpness in preparation, it may be inferi'ed that they are by no 

 means merely ornamental appendages ; beyond the spine-row, doing duty apparently for 

 the molar tubercle, is a second row of five or six spines, set closely together, the first 

 one or two short, the rest long, the furthest back being much the longest ; the slender 

 palp, exceeding the length of the trunk of the mandible, is fixed on a projection over the 

 space between the two spine-groups, and has three almost equal joints, the second a very 

 little longer than the first, and the first than the third ; some four slender spines or setse 



