291 



The head is spherical and entirely occupied by highly pigmented 

 eyes. Antennae I in males have a proximally bulged 1st segment in the 

 flagellum, which is stretched toward the apex; the flagellum in males 

 barely broadens and gently tapers toward the end. Antennae II in females 

 are shorter than or equal to antennae I, in males longer, mainly because 

 of the elongation of the segments. Maxillae I have a small oval inner 

 lobe. The masticatory process of the mandibles has a flat grating surface; 

 the 2nd segment of the mandibular palp is much longer and broader 

 than the 3rd segment. The basal segment of pereopods I-II is almost 

 not broadened. The 2nd segment of pereopods VII is longer than the 

 distal part of these legs. The epimeral plates have rounded margins. The 

 basipodite of uropods III is longer than the rami. The telson is small. 



In external appearance these crustaceans resemble representatives of 

 the family Hyperiidae, coming closer to Parathemisto in body propor- 

 tions. Morphological peculiarities indicate the affinity of Cyllopus to the 

 family Vibiliidae. 



Type species: Cyllopus magellanicus Dana, 1852. 



Notes: While revising this genus, Barnard (1930) considered C. levis 

 Bovallius, 1889 a doubtful species and the remaining known species as 

 synonyms of C. magellanicus and C. lucasi. Hurley (1955) suggested 

 retention of C. macropis (Bovallius, 1887) based on the incomplete 

 segmentation of pereopods VII. 



Analysis of extensive material from the environs of New Zealand, 

 however, revealed wide variation in the segmentation of pereopods 

 VII and the age-related nature of other less significant differences, 

 thereby enabling confirmation of the identity of C. macropis with 

 C magellanicus. 



At present, the genus includes two species, distributed in the cold 

 waters of the Southern Hemisphere. 



KEY TO SPECIES OF GENUS CYLLOPUS 



1. Second segment of pereopods VII almost oval, with uniformly con- 

 vex margins; 5th segment of pereopods I not broadened, its length 

 more than width; process of 5th segment of pereopods II extends to 



middle of 6th segment 1 . C. magellanicus Dana. 



— Second segment of pereopods VII narrows distally, posterior margin 

 concave; 5th segment of pereopods I broadens distally, its maximum 

 width equal to or more than length; process of 5th segment of pere- 

 opods II extends beyond middle of 6th segment 



2. C. lucasi Bate. 



