24 



Remarks. This family, answering to the subfamily ^Etidiina of Giesbrecht, 

 forms, as it were a transition between the Pseudocalanidce and Euchcetidce. One of 

 the forms, indeed, now comprised within the present family was referred by Boeck 

 to the genus Pseudocalanus and another form to the genus Euchceta. I think, 

 however, that Dr. Giesbrecht is right in keeping these forms apart from both the 

 above-named families. This family comprises as yet no less than 9 different genera, 

 4 of which are represented in the fauna of Norway. 



Gen. 6. ^EtldeuS 1 ), Brady, 1883. 



Syn: Pseudocalanus Boeck (part). 



Generic Characters. Cephalosome in female highly vaulted anteriorly, 

 almost carinated dorsally, and projecting below into a strong bifurcate rostrum, 

 in male far less vaulted, and without any trace of a rostrum. Last segment of 

 metasome produced behind on each side to a strong mucroniform process more 

 developed in female than in male. Urosorne in female comparatively short, ge- 

 nital segment very protuberant below, caudal rami less shortened than in the 

 other forms, with the appendicular bristle of the inner corner unusually long and 

 slender, outermost (5th) apical seta only present as a rudiment. Urosome of male 

 very slender, with the anal segment considerably shortened, almost inconspicuous. 

 Eye subventral, of a somewhat irregular form and obliquely disposed, with a 

 distinct lenticular body below. Anterior antennae in female comparatively slender, 

 with some of the bristles of the anterior edge rather elongated, last joint very 

 small and imperfectly defined from the penultimate one; those in male shorter, 

 with the 7 proximal articulations well defined, whereas a fusion has taken place 

 of some of the others. Posterior antennae with the outer ramus but little longer 

 than the inner, and 7-articulate. Posterior maxillipeds not much elongated, 2nd 

 basal joint fusiform, terminal part comparatively short, reflexed. Inner ramus of 

 2nd pair of legs imperfectly biarticulate. Left leg of last pair in male very 

 slender, 5-articulate, right leg wholly wanting. 



Remarks. This genus was established in the year 1883 by Brady, to 

 include a Calanoid procured during the Challenger Expedition in the Indian 

 Ocean, and regarded as new to science. The genus, though insufficiently charac- 



*) This name is spelt by Brady JEtidms ; but, as recently observed by Dr. Giesbrecbt, 

 this is unquestionably incorrect, as it is derived from the Greek word aeTiSeu;, an eaglet. 



