45 



strong, spiniform. Last pair of legs extremely small, though distinctly 3-articulate, 

 basal joint rather thick and armed at the end inside with densely crowded spinules, 

 last 2 joints unarmed, middle one very short, terminal joint straight, digitiform. 



Male not differing much from female in its external appearance, though 

 having the urosome considerably more slender, and, as usual, 5-articulate. Anterior 

 antennae consisting of only 21 articulations. Both pairs of maxillipeds consider- 

 ably transformed, the anterior ones very small, the posterior ones with the terminal 

 part reflexed. Last pair of legs very slender, right leg 5-articulate and reaching 

 beyond the antepenultimate joint of left. 



Colour dark yellowish brown. 



Length of adult female 1.60 mm., of male 1.40 mm. 



Remarks. In its general appearance this Calanoid somewhat recalls the 

 JEtideid described above as Bryaxis brevicornis, Boeck, having a similar robust 

 form of body and also comparatively short and densely setous anterior antennae. 

 On a closer examination, however, it is found to differ very essentially, so that 

 it cannot even be included in the same family. It also somewhat resembles the 

 Mediterranean form, Phaenna spinifera, Glaus; but this Calanoid has the body 

 still more robust, whereas its anterior antenna are considerable more slender. 



Occurrence. I have found this peculiar Calanoid occasionally in several 

 places on the Norwegian coast, from the Christiania Fjord to Vardo, and always, 

 like the species of the genus Undinopsis, only close to the ground in depths ranging 

 from 20 to 50 fathoms. It accordingly is a true bottom-form, unlike what is 

 generally the case with the Calanoida. Out of Norway this form has not yet 

 been found. 



G-en. 12. XanthOCalailUS, Giesbrecht, 1892. 



Generic Characters. Body less robust than in the preceding genus, with 

 the cephalosome more or less distinctly defined from the 1st pedigerous segment, 

 rostral prominence with 2 soft posteriorly-pointing tentacular appendages. Lateral 

 lobes of last segment of metasome produced to more or less prominent 'acute 

 lappets. Urosome short, of a structure similar to that in the preceding genus. 

 Two eyes present, separated by a distinct interspace. Anterior antennae in female 

 rather slender, 24-articulate, bristles of anterior edge not very strong, 2 of them 

 issuing from the basal joint finely plumose; those of male richly supplied with 

 sensory appendages, and having some of the articulations coalesced. Posterior 



7 Crustacea. 



