220 



Occurrence. I have hitherto only met with this form in the uppert part 

 of the Christiania Fjord, at a short distance from the town. It occurred here 

 not unfrequently in a depth of 3 6 fathoms on a muddy bottom covered with 

 decaying algae. 



Distribution. British Isles (Scott). 



141. Ameira tenella, G-. 0. Sars, n. sp. 



(PI. CXLV). 



Specific Characters. Female. Body exceedingly slender, narrow linear 

 in form, with the posterior division fully as long as the anterior. Last caudal 

 segment about the length of the preceding one. Caudal rnmi unusually much 

 produced, being about 3 times as long as they are broad, and slightly tapered 

 distally, apical setae much elongated. Anterior antennae very slender, considerably 

 exceeding in length the cephalic segment, and clothed in their outer part with 

 exceedingly long setae, 3rd and 4th joints of about equal length, terminal part 

 scarcely longer than those 2 joints combined. Posterior antennae with the outer 

 ramus less narrow than in the other species. 1st pair of legs moderately slender, 

 outer ramus somewhat exceeding half the length of the inner, terminal joint of 

 the latter narrow linear, fully 3 times as long as the very small 2nd joint, both 

 together a little shorter than the 1st. Natatory legs slender, with the setae some- 

 what reduced in number. Last pair of legs with the distal joint very narrow, 

 sublinear in form, densely ciliated along the outer edge and the proximal part 

 of the inner, apical seta very slender and elongated, inner expansion of proximal 

 joint comparatively short, with 4 marginal setae. 



Colour not yet ascertained. 



Length of adult female 0.53 mm. 



Remarks. By the very slender form of the body, the elongated anterioi 

 antennae and the unusually much produced caudal rami, this form exhibits a per- 

 plexing similarity to a species described by Mr. A. Scott under the name of 

 Ameira gracilis, and indeed at first I believed both to be identical. On a closei 

 examination of the specimens, I have however found some very striking differences 

 in the structure of the appendages, which seem to forbid such an identification 

 Thus the shape of the last pair of legs is totally different, and also the mutua" 

 relation in length of the articulations in the anterior antennae appears to bt 

 very unlike. __ 



