10 



Occurrence. I have found this form in the same localities and at 

 about the same depth as the preceding species. At Riser only one or two speci- 

 mens were obtained, whereas at Korshavn this form seems to be rather abundant 

 in some places. 



Distribution. Scottish coast (Scott). 



Fam. Platycopiidae. 



Gen. Platycopia, G. O. Sars, 1911. 



Generic Characters. General form of body resembling that of Pseudo- 

 cyclopia. Last trunkal segment, however, well defined from the preceding one, 

 and urosome composed in both sexes of only 4 segments. Anterior antennae 

 short and stout, though composed of rather a great number of articulations, 

 and only slightly differing in the two sexes. Posterior antennae with the outer 

 ramus much larger than the inner. Oral parts considerably deviating in struc- 

 ture from the usual Calanoid type. Anterior lip narrowly produced at the end. 

 Mandibles with the masticatory part only slightly expanded, palp comparatively 

 slender, with the outer ramus larger than the inner. Maxillae with the masti- 

 catory lobe very coarsely built, palp comparatively less fully developed than in 

 most other Calanoida. Anterior maxillipeds cyclopoid in structure, the outer 

 joints being armed with stout unguiform spines. Posterior maxillipeds more 

 resembling those in other Calanoids. 1st pair of legs rather unlike the suc- 

 ceeding ones, with both rami imperfectly developed and without true spines; 

 the remaining pairs very strongly built, with the rami broad and flattened, the 

 outer one the larger, and having 2 successive spines outside the 1st joint; natatory 

 setae for the most part converted to short flattened spines. Last pair of legs 

 built on the very same type as the preceding ones; those of male having the 

 outer ramus slightly transformed and alike on both legs. 



Remarks. This genus was established by the present author in the 

 year 1911, to include a remarkable deep-water Calanoid, P. perplexa, the 

 closer examination of which revealed a most perplexing mixture of char- 

 acters tending on the one side to the genus Pseudocydopia, on the other side 

 to Pseudocyclops, though these 2 genera, according to the definition given by 

 Giesbrecht, in reality belong to 2 very different sections of the Calanoida, the 



