214 THE VOYAGE OF H.M.S. CHALLENGER. 



The telson (fig. 20) exhibits an aspect most characteristic of the genus and quite 

 different from that usually met with in the Mysidse, save in the genus Erythrops, G. 0. 

 Sars. It is very short, lamelliform, fully as broad at the base as it is long, having the 

 lateral edges armed on either side with five strong denticles, and the apex narrowly 

 truncate, bearing in the middle two very long and densely ciliate setee. 



The uropoda (fig. 19) have the terminal plates very slender and fringed all round 

 with strong plumose setae. The inner 2)late is much the shorter and lanceolate in form, 

 with the base considerably dilated and containing a fully developed auditory apparatus, 

 the otolith being rather large and of globular form. The outer plate is about one-fifth 

 longer than the inner, and very narrow, linear, though somewhat curved outwards and 

 truncate at the tip. 



As to colour, the specimens preserved in glycerine were of a uniform light brownish 

 hue, without any trace of the stellate pigmentary spots found in the species of the 

 preceding genus. 



Habitat. — Of this form only three specimens were found in the collection, taken at 

 the surface of the sea in the North Pacific. The following is a list of the localities, with 

 dates appended : — 



Quite recently I have had an opportunity, through the kindness of Mr. Hoyle, of 

 examining another specimen, a young female, of apparently the same species, taken 

 April 9, 1876, in the Atlantic. The specimen was mounted on a glass slide together with 

 a small Cephalopod and several other surface animals. 



56. EuchcBtomera tenvis, G. 0. Sars (PL XXXVII. figs. 21-24). 



Uachmtomera tenuis, G. 0. Sars, rreliminaiy Notices oa the Cliallenger Scliizopoda, No. 53. 



Specific CJiaracters. — Form of body more slender than in preceding species, tail 

 especially much narrower, with last segment greatly elongate. Carapace comparatively 

 large, posterior emargination rather narrow, rostral projection very slight. Eyes greatly 

 expanded, broader than long, and close together. Antennal scale very narrow, six times 

 as long as broad, denticle of outer corner small. Legs exceedingly slender, with scattered 

 but rather long bristles. Telson having lateral edges perfectly smooth, apex with a 

 slight dentiform projection on either side. Length, 8 mm. 



