4 6 DISCOVERY REPORTS 



Gnathopod i feebly subchelate, 6th/ joint shorter than 5th, oblong, upper margin 

 slightly indented, lower margin spinose, passing into the short, oblique and minutely 

 fimbriate palm by a rounded angle, finger short, stout, curved. Gnathopod 2, 6th joint 

 oval, half length of 5th, with a short straight almost transverse palm, with one short 

 spinule at the angle. 



Peraeopod 3, 2nd joint broadly ovate, hind margin very obscurely notched, anterior 

 margin spinulose distally, 4th joint moderately expanded, 3rd-6th joints very feebly 

 armed with a few spinules and setules. Peraeopod 4, 2nd joint less broadly ovate, other- 

 wise like peraeopod 3. Peraeopod 5, 2nd joint more broadly expanded than in peraeopod 

 4, but more oblong than in peraeopod 3, longer than the other joints together, 4th joint 

 less expanded than in peraeopods 3 and 4, 3rd-6th joints rather more strongly armed 

 with spinules. 



Uropods 1 and 2 extending very slightly beyond apex of uropod 3 , rami shorter than 

 peduncles, acuminate, spinose, inner ramus of uropod 2 not constricted. Uropod 3, 

 rami longer than peduncle, 2nd joint of outer ramus well developed, inner ramus ex- 

 tending to middle of 2nd joint of outer, both rami without spines or setae. 



Ambasiopsis uncinata, n.sp. (Fig. 10). 



Occurrence: St. 170. South Shetlands. 1 <J 8 mm., 1 ? 14 mm., 2 ovig. $$ 12, 13 mm. 



Description. Closely resembling georgiensis in general, but: pleon segment 3 with 

 postero-inferior angle quadrate, but not sharp at the corner; segment 4 with a high 



Fig. 10. Ambasiopsis uncinata, n.sp. a. Gnathopod 1. 

 b. Pleon segments 3 and 4. 



conical, somewhat unciform, tooth, pointing slightly forwards; telson rather shorter in 

 proportion to its breadth ; all the antennal fiagella with one more joint apiece ; gnathopod 

 2 stouter, 5th joint broader, more triangular, 6th joint markedly narrower than 5th, 

 upper margin not indented, lower margin more closely spinose especially near junction 

 with palm; hind margins of 2nd joints of peraeopods 3-5 distinctly though shallowly 

 notched. 



The 3rd joint of antenna 2 is not expanded as in M . faeroensis , though the S specimen 

 is probably not fully grown. 



