Copepoda from the Falkland Islands. 9 



This Oithona was tolerably frequent in all the three marine 

 tow-net samples already mentioned, and was the only one 

 observed. In this species the rostrum is short, stout, and 

 hook-like, and is turned downward at nearly a right angle 

 (fig. 12). 



This species has frequently been recorded under the name 

 of Oithona similis, but, according to Prof. G. O. Sars, 

 O. similis and 0. helgolandica are identical, and the latter, 

 being the older name, should be preferred. 



The distribution of Oithona helgolandica extends apparently 

 from the Arctic to the Antarctic Oceans. Dr. Giesbrecht 

 records it from 71° south latitude, and Prof. G. O. Sars has 

 examined specimens collected off the coast of New Zealand, 

 and " compared them with northern specimens, without 

 being able to detect any difference whatever "*. The 

 Falkland specimens measured fully 1 mm. in length. 



Fam. Cyclopidae. 

 Genus Cyclops, Midler, 1776 (part.). 



Cyclops prasinus, Fischer. (PI. II. figs. 5-7.) 



1860. Cyclops prasinus, Fischer, Beitr. z. Kenntn. d. Entomostraceen, 

 pp. 652-654, Taf. xx. figs. 19-26 a. 



This species occurred very sparingly in a gathering from 

 a small fresh-water pond near the sea. Besides the northern 

 distribution of the species, it has also been reported from 

 Yaldivia, Chile, and from the Argentine, In this species the 

 antennules are twelve-jointed and the fifth pair of legs in the 

 female are each provided with three elongated setse (fig. 6). 

 The caudal segments are tolerably short (fig. 7). 



Cyclops michaelseni, Mrazek, var. falklandi. 

 (PI. I. fig. 3 ; PI. II. tigs. 8, 9.) 



The small Cyclops recorded under this name occurred in 

 several of the fresh-water gatherings from the Falklands. 



This form is apparently identical with Cyclops michaelseni, 

 Mrazek, except in the structure of the last pair of thoracic 

 legs, and in this respect it agrees better with Cyclops lobu- 

 losus. Ekman. In that species, however, the antennules are 

 described a? consisting of twelve joints, and the proportional 

 lengths of the various joints also differ. Both Cyclops 

 michaelseni, Mrazek, and Cyclops lobulosus, Ekman, have 

 already been recorded for the Falkland Islands. In the 



* ' Crustacea of Norway,' vol. vi. parts 1 & 2, p. 9 (1913). 



