the 'Challenger' Amphipoda. 207 



elevation. The third segment has a similar dorsal tooth with 

 three processes on either side ; the fourth has only the dorsal 

 process ; the fifth is simple ; the sixth is produced into sharp 

 angles behind the insertion of the telson. 

 , The first three epimera are bidentate below, the last three 



are posteriorly bidentate, the fourth widely excavated below, 

 with the hinder tooth much above the anterior one. The 

 third joint is produced in all the pereiopoda, in the last three 

 tile fourth joint also ; in each of which the first joint is a flat- 

 tened plate with the lower and hinder margin conspicuously 

 * cut into variously sized teeth, six in each of the first two, 



seven in the last. The peduncles of the last uropods are 

 short and broad, acutely produced behind. The telson is 

 concave above, rather deeply emarginate, ending in two 



sharp points. 



Iphimedia pacifica, n. sp. 



Head with depressed rostrum and bidentate sides. In the 

 upper antennae the second and third articuli, in the lower the 

 third articulus, are denticulate. The last segment of the 

 pereion and first two of the pleon dorsally bidentate. All the 

 segments of the pereion have the lower margin produced 

 acutely backwards, the seventh segment conspicuously. This 

 * is the case also with the last three epimera, the first three and 



the last pleon-segments. The first three pleon-segments have 

 likewise a medio-lateral tooth, that on the third being bent 

 upwards and serrulate below. The last three pereiopoda 

 have the first joint with a serrate margin, dilatedly rounded 

 above, the lower hinder angle produced into a tooth. 



The telson is square in general form, emarginate, with a 

 distal tooth at each side. 



Family Caprellidae, Dana. 



Dodecas elongata^ n. g. et sp. 



Gen. char. — The mandibles having an elongate triarticulate 

 palp. Six pairs of feet attached to the pereion, the fourth 

 segment having none. Branchial vesicles at the base of the 

 second gnathopods, the first pereiopods, and attached to the 

 footless fourth pereion-segment, the rudimentary pleon havin 





two pairs of biarticulate appendages. 



Sjjec. char.—Body smooth; eyes prominent; first two 

 segments of pereion very long and slender in the male, much 

 shorter and somewhat thicker in the female. The wrist or 

 fourth joint of the second gnathopods very long in the male, 

 short in the female. The first pereiopods exceedingly slender; 

 the third pereiopods also slight, only four-jointed. 



