of the North Atlantic and of North-Western Europe. 665 



(Type, Streptoleberis erenulata, G. S. Brady, from Noumea.) 



The animal is unknown. We had hoped from the appearance of two dried 

 specimens of S. favosa, that they might have been alive when dredged. These 

 were carefully softened and examined, but such fragments of the animal as 

 remained were only the relics of one which had been dead when dredged, and 

 very dirty. One or two minute fragments of limbs seem peculiar, the caudal 

 laminse had only six ungues, all of considerable size, and one of them (detached 

 but probably the last) shows a large and conspicuous spine- shaped process on the 

 middle of the outer margin, both the inner and outer margins beyond the spine- 

 shaped process being ciliated. The antennae resemble most closely in character 

 the same organs in Paramekodon, having no appendicular branch but two setae in 

 its place, the basal joint somewhat smaller than usual, the length exceeding the 

 breadth, first joint of the swimming branch rather slender. 



1. Streptoleberis favosa, n. sp. 

 (Plate Lix., figs. 16-18 ; Plate lxil, figs. 20, 21.) 



It is difficult to apply any term to the curious outline of this species, but it 

 may perhaps be said that the portion posterior to the antennal sinus is in the shape 

 of a cone, of which the hinder extremity is the summit. The ventral margin is 

 evenly but only slightly arched throughout to the end of the posterior process, in 

 front it sweeps inwards almost at a right angle to form the antennal sinus ; dorsal 

 margin very boldly arched from the extremity of the rostrate process round the dorsal 

 and posterior margins till it forms in the centre of that margin a blunt, conical 

 termination ; the rostral process is broad and widely rounded at the extremity, 

 where it bends downwards ; the antennal sinus is large and widely gaping. Surface 

 of valves very uneven, sculptured with deep pittings, a ridge running parallel 

 with the dorsal margin, and a large boss-like protuberance occupying the hinder 

 portion of the valves, and in front of this are other irregular humps. The greatest 

 height is equal to about three-fifths of the length, and the greatest width three- 

 fourths of the height. Viewed from above, the form is irregularly oblong, the 

 sides much undulated, in front the termination is very broad and of unusual 

 length, the posterior extremity is linguiform, this portion of the outline being 

 caused by the compressed extremity of the valves which lies beyond the boss-like 

 protuberance. Length, 1*3 mm. ; height, -8 mm. 



We have figured in PI. lxii., figs. 20, 21, a fragment of a caudal lamina; 



