REPORT ON THE AMPHIPODA. 885 



the lower margin ; the second segment is similar to the first, but deeper ; the third has a 

 smaller central process with a tubercle or denticle below on each side, a little in front, 

 while to the rear from the hinder margin rise three processes, or one that is tridentate, 

 while beyond this on either side there is an upward-bent lateral process ; the fourth 

 segment begins with a small hump and a depression, the latter being followed by a central 

 process with serrate edges, and this by a second at the distal end of the dorsal line ; the 

 fifth segment is short and unarmed ; the sixth, also short, carries a central, and on either 

 side of it a lateral, process. 

 Eyes not observed. 



Upper Antennse. — The first joint of the peduncle distally dilated and produced in 

 three long processes, one shorter than the other two ; the second joint subequal in length, 

 distally produced in two long processes ; the third joint much shorter and more slender, 

 not nearly reaching to the end of the processes of the preceding joint, with two small 

 distal angles ; the flagellum broken, but at least of more than eight joints, the first very 

 long, longer than either the first or second of the peduncle apart from their processes, 

 equal to about four of the succeeding joints of the flagellum ; the other joints successively 

 diminish in thickness, but not in length, each carrying a small distal spine in a group of 

 setules ; the first joint has three such groups, and from the fifth to the eighth there is 

 an additional group at the centre of the margin. 



Lower Antennae. — The composite first and second joints show two large processes, the 

 upper with its upper margin serrate and carrying spines, the lower much smaller, both 

 apparently forming part of the first joint, while the second is not prominent, with the 

 gland-cone small and obscure ; the third joint has one rather long, and two short, distal 

 processes ; the fourth joint, much longer than the third, has two long distal processes, 

 the lower longer than the upper, and two small processes, one on either side between the 

 larger ones ; the fifth joint is long and straight, with two small adjacent distal processes 

 above and one below, and is nearly as long as the total length of the previous joint ; the 

 flagellum, rather longer than the peduncle, consists of eleven, or possibly twelve joints, 

 of which the first is very long and tapering, equal to the four following joints united, 

 which with the rest successively decrease in thickness but not in length. 



Upper Lip with the distal margin bilobed, one lobe rather larger than the other, the 

 ciliatiou not strong. There appear to be traces of a small inner plate, adnate at the 

 distal corners to the surface of the outer. 



Mandibles. — The shaft much bent so as to present a deep concavity between the base 

 and the palp, where it makes a right angle, the upper margin passing in a sinuous line 

 to the narrow cutting plate, which is apically divided into some small teeth, about five 

 or six in number, and lightly clasps the secondary plate, which is of nearly equal length, 

 apically divided into five teeth on the left mandible, two of the teeth being double ; on 

 the right mandible this plate is much more slender, and so far as observed has much 



