28 



indeed has given rise to the specific name here proposed. In the structural 

 detail also some minor differences are found to be present, especially as regards 

 the posterior maxillipeds and the caudal rami. 



Occurrence. Several specimens of this form were collected, many years 

 ago, at Skraaven, Lofoten islands. They occurred in a depth of about 6 fathoms, 

 on a sandy bottom partly overgrown with algae. 



Gen. 11. HallCy ClOpS, Norman, 1903. 



Syn : Hemicydops Claus (not Boeck). 



Generic Characters. Body of the usual cyclopoid shape, and somewhat 

 depressed in its anterior part. Head confluent with the 1st pedigerous segment, 

 and having the rostrum bent in against the ventral face. Anterior antennae short, 

 with the number of joints greatly reduced; those in male strongly hinged. Posterior 

 antennae with the outer 2 joints confluent. Mandibles with one of the cutting 

 teeth much larger than the others, setae of rudimentary palp comparatively short. 

 Maxillary palp forming a small lamella not extending beyond the masticatory 

 lobe, and terminating in a short spine accompanied by one or two setae. Anterior 

 maxillipeds with the digitiform lobe, issuing from the end of the 1st basal joint 

 anteriorly, rather small and terminating in 2 unequal seta3. Posterior maxillipeds 

 imperfectly developed, being composed of 2 or 3 joints only. Natatory legs built 

 upon the usual cyclopoid type, but having the rami not nearly so broad as in 

 Euryte. Last pair of legs with the proximal joint more or less completely 

 coalesced with the corresponding segment, distal joint broad lamelliform and 

 edged with partly ciliated setae. 



Remarks. This genus was established in the year 1893 by Claus, to 

 include the form generally recorded as Cyclops ceqvoreus Fischer. As, however, 

 the name he proposed, Hemicyclops, had been preoccupied by Boeck, to designate 

 another very different genus, not even belonging to the same section, it has been 

 changed by Norman to Halicyclops. The genus is nearly allied to Cyclops, but 

 differs in the imperfect development of the posterior antennae and of the posterior 

 maxillipeds, as also in the peculiar structure of the last pair of legs. In addition 

 to the typical form, to be described below, another nearly-allied species has been 

 recorded by the present author from the Chatam islands as H. propinqvus, and 

 a 3rd species, not yet described, occurs, as a true planktonic form, in the Caspian 



