297 



denticle on the inner margin, which projects backward. The rami are 

 about equal to the basipodite in length; the endopodite is slightly broader 

 and longer than the exopodite; the outer margin of the endopodite and 

 exopodite are coarsely denticulate; the inner margin of the exopodite is 

 finely denticulate except distally where two-four coarse denticles occur. 

 The basipodite of uropods II is broadened distally and extends to the 

 end of the telson; its length hardly exceeds its maximum width and the 

 inner margin terminates in an acute denticle. The rami are longer than 

 the basipodite; the endopodite is distinctly longer and broader than the 

 exopodite, uniformly broadened along the entire, length, and constricted 

 only toward the apex. The basipodite of uropods III has parallel margins, 

 the inner distal angles are acute, and its length is 2.5 times its width. 

 The rami, about half the length of the basipodite, are equal in length; 

 the endopodite is broader than the exopodite; the outer margin of the 

 exopodite is smooth proximally but indistinctly denticulate distally; the 

 inner margin is finely serrate; the endopodite is coarsely denticulate on 

 both sides except in the proximal part of the outer margin. The telson is 

 small and roundish-triangular. 



Distribution: A stenothermic, cold-water, circum-Antarctic species; 

 all catches have occurred south of the Antarctic Convergence. 



244 IX. Family CYSTISOMAXmAE Willemoes-Suhm, 1875 



Some of the largest hyperiideans belong to this family: the females may 

 reach 140 rnm while the males are generally smaller (50-70 mm). The 

 body integument is distinguished by exceptional transparency, so much 

 so that the inner organs are visible through it. The head is unusually large 

 and without a rostrum. The ventral (in males — frontoventral) surface of 

 the head is flat and separated from the lateral surface by a dentate keel 

 (marginal denticles). The eyes occupy dorsal and partly lateral sides 

 of the head. Antennae I are conical with poorly demarcated segments. 

 Antennae II present on the ventral surface but reduced to short spines. 

 The oral appendages are likewise notably reduced. The mandibles have 

 no palp. Maxillae I lack an inner lobe; maxillae II have one lobe, with 

 the inner lobe in the form of a small tubercle or absent. The maxillipeds 

 have a well-developed unsplit medial lobe, thickened at the end, and 

 with a concave distal margin. 



The first two somites of the pereon are generally fused. Pereopods 

 I-II are very short, with a chela, and the other pereopods long and thin. 

 Pereopods VII are shorter than pair VI and in females have a modified 

 distal part forming a unique subchela. The gills are located at the base 

 of pereopods II-VI or IV-VI. The oostegites occur on somites II-V of 

 the pereon. The somites of the pleon are lower than those of the pereon. 

 No border is discernible between the fused urosomites II-III. Uropods 



