GAMMARIDEA. 929 



short, slender beak, abdomen subcarinate. Four anterior thoracic 

 segments entire at posterior margin, fifth sinuous behind, and sixth 

 and seventh sparingly dentate ; first three abdominal segments den- 

 tate on the back, and sparingly acuto-nodose on the sides, the rest 

 naked. Three anterior epimerals entire, obtuse, fourth bidentate 

 behind, three following narrow and posteriorly acute. First joint 

 of last six legs subquadrate, unidentate behind, and posterior angle 

 acute. Inferior antennae the longer, shorter than half the body. 

 Legs naked; four anterior quite small, hands minute; next four 

 larger; remaining six a little longer, subequal, third joint triangular, 

 posterior apex being prolonged and acute. 



Plate 63, fig. 3 a, animal, enlarged; b, upper view of head. 



Hermite Island, Tierra del Fuego. Collected by Lieutenant Case. 



Length, four lines. Thorax inflated. Abdomen subcarinate ; the 

 first three segments have a triangular tooth at middle on the back, 

 and behind this two larger teeth (side by side), with truncate top. 

 The head has a short linear obtuse beak. Base of superior antennae 

 much the shortest, the whole length of antenna about three-fourths 

 the inferior pair. The four anterior feet are slender and much 

 smaller than the following. The six posterior are rather short, ter- 

 minal joint to which claw is articulated nearly cylindrical, claw 

 short ; third joint having the shape of a very obtuse-angled triangle, 

 the obtuse angle at its apex, and the prolongation of the posterior 

 apex in seventh pair, nearly as long as the joint ; posterior angle of 

 fourth joint also acute. The posterior stylets extend back nearly to 

 same line with the first. 



This species is allied to the Acanihosoma hystrix of Owen (Sir John 

 Ross's Second Voyage in Search of a Northwest Passage, 4to., Lon- 

 don, 1835, Appendix, p. xci. PI. B, figs. 4, 5, 6, 7). 



Amphithoe (Jphimedid) nodosa, Dana, Proc. Amer. Acad. Sci., ii. 217. 



Iphimedia FISSICAUDA. 



Carpus compressum, epimeris magnis. Oculi reniformes. tegmentum 



233 



