44 



without distinct coxal plates. Metasome comparatively short, with the anterior 

 segments sometimes coalesced, telson generally well denned, linguiform. Both 

 pairs of antennae, at least in female, short and subequal in length, originating 

 close together, the one pair beneath the other. Oral parts modified for perfora- 

 tion and suction. Legs composed of the normal number of joints, the basal and 

 ischial ones being rather slender, and forming together a genicular bend; 1st pair, 

 as a rule, much stronger than the others and subcheliform ; the 2 succeeding pairs 

 likewise subcheliform, but much feebler ; the 4 posterior pairs ambulatory. Pleopoda 

 chiefly branchial in character, 1st pair large, more or less covering the others. 

 Uropoda with the outer ramus extending upwards, so as generally to arch over 

 the base of the telson. Incubatory pouch apparently not formed by distinctly de- 

 fined lamellae. 



Remarks. — In their general outward appearance, the forms belonging 

 to this family somewhat recall the Tanaldw, having a similar long and nar- 

 row body, and in some cases, there is even to be found a slight attempt at a 

 cheliform structure of the 1st pair of legs. But otherwise, the two families are 

 widely different. The structure of the oral parts would seem to point to a para- 

 sitic habit, but in none of the forms has the mode of parasitism as yet been 

 stated. The manner in which the metasome terminates is very peculiar, and un- 

 like that found in other Isopoda; for the telson is well defined from the last 

 segment, and more or less strongly deflexed, whereas the outer ramus of the uro- 

 poda extends upwards so as to arch over the base of the telson, thereby giving 

 the caudal fan a somewhat cup-shaped appearance. It is indeed from this 

 character that the name Anthura, given to the typical genus, lias been derived. 

 In some of the exotic forms, however, this peculiar formation would appear to 

 be less pronounced than in the northern forms. Several genera have been esta- 

 blished in recent times, amounting to about 10 in all. Of these, only 2 are repre- 

 sented in the fauna of Norway. 



Gen. 1. Calathura, Norm. & Stebb., 1886. 



Generic Characters. — Body moderately slender, with the 2nd segment of 

 mesosome very movably connected, both with the preceding and succeeding segments, 

 dorso-lateral carinas in all the segments well marked. Metasome comparatively 

 short, with the segments not very distinctly defined, though apparently present 

 in the normal number. Eyes imperfectly developed, or quite wanting. Antennas 

 subequal in length, both pairs having the flagella multi-articulate; the superior 



