Amphipoda Synopidea. 9 



first joint is very short; the second very long, tumid, irregularly ovate, 

 carrying a single plumose hair near the outer end; the last joint is mi- 

 nute, scarcely a tenth of the length of the preceding, with two very 

 long, plumose hairs at the tip. At the base of the mandibular palp there 

 are two strong, denticulated, masticatory projections. 



The first pair of maxillce [PL I, fig. 8] consist of a short basal 

 joint and two robust laminœ; the outer one is the longest and broadest, 

 carrying a row of nine to ten strong spines at the end, and another 

 row of six spines a little behind, near the middle of the lamina. The 

 inner lamina is fringed with long hairs along the inner margin, and 

 carries a row of 7 — 8 unequal spines at the end. 



The second pair of inaxillœ [PI. I, fig. 9] consist of two laminae; 

 the inner is the larger, ovate, with a row of five peculiar, denticulated 

 spines at the end [PI. I, fig. 10], and a longitudinal row of 14 — 15 

 long, simple spines on the inner side of the lamina. The inner lamina 

 is oblong, with about a dozen long bristles at the top. 



The maxillipeds [PI. I, tig. 11] are very large, when closed, totally 

 covering the other oral organs. The basal joints are coalesced, the 

 following free; both laminœ are ovate, fringed with long, plumose 

 hairs, the first along the inner, the second along the outer margin. The 

 palp is four-jointed, the first joint is short and thick, the second three 

 times longer than the first, fringed along the outer margin with long, 

 plumose hairs. The third joint is narrower, half as long as the second, 

 with long, simple hairs at the end; the fourth joint is very minute, 

 about a fifth of the length of the preceding. 



The pereion. The first segment is a little longer than the second, 

 but shorter than the third, the third to fifth are equal, the sixth is much 

 longer, longest of all, the seventh segment is longer than the fifth. 

 The surface of the segments is very smooth, the posterior corners 

 are feebly rounded. 



The epimerals (PI. I, fig. 1) are well developed, but very thin and 

 totally pellucid; they are very easily overlooked, which may be the 

 reason why they are not described by Dana, but only mentioned in the 

 explanation of the plates and figured from the third segment together 

 with the correspondent leg. (Dana 1. c. p. 996, pi. 68, fig. 6, e). 

 The epimerals, of the first and second segments are as long as the 

 segments, of Un irregular shape and only half as deep as long. The 

 epimerals of t\ e third segment [PI. I, fig. 13] are enormously de- 

 veloped; they arv quadrangular with the upper corner (the articulation with 



Nova Acta Keg. ijoc. Sc. Dps. Ser. III. 2 



