118 MESSES. NOEMAN AJSID STEBBING- ON THE 



Eyes none. 



Upper antennae in female strongly built, four-jointed ; lower pair more slender, seven- 

 jointed, the last rudimentary. 



Gnathopods strong, of the usual form. 



Perseopods slender, with a long finger, terminating in a long nail ; the anterior pairs 

 more spined than the posterior, the latter not having the basos markedly constricted in 

 its upper half. 



No pleopods. 



Uropods conical, having only a single branch without any vestige of an outer one, 

 composed of two joints. The first represents the peduncle, the second the branch ; the 

 la.tter is nearly twice as long as the former. 



The only other genus of this family which has the uropods consisting of a single 

 branch is Tanais, from which this is at once distinguished by the absence of pleopods 

 and other characters. 



To Strongylura it has perhaps the closest affinity, and we have followed the wording 

 of the description of that genus, as given by Sars and quoted in this paper, in order to 

 bring out the points of difference. In Strongylura the uropods are two-branched ; in 

 Tanaella they are one-branched. 



Tanaella unguicillata, n. sp. (Plate XXIV. fig. iv.) 



The rostrum (iv. d) is short and not acute ; the eye-processes are difficult to observe 

 in the single specimen obtained ; they seem to be set back in a kind of socket. The 

 carapace is longer than wide, the hinder portion bulging laterally, so that the diameter 

 is there greater than in the succeeding segments of the parallel-sided perseon. Of the 

 free perseon-segments the sixth is scarcely longer than the first, the second is longer 

 than either, and the third, fourth, and fifth longer than the second. The first five 

 pleon-segments increase very slightly in width distally. The last segment is also, in 

 its anterior portion, rather wider than the fifth, and in length fully equals that of the 

 four preceding taken together ; from the attachment of the uropods it narrows rapidly 

 to an almost pointed termination. 



The upper antennas (iv. L*) are short and thick, the first joint shorter than usual, 

 stout and curved; the second is shorter, and thick in proportion to its length, and 

 is furnished at its end with a stiff spine, which lies parallel with and close to the short 

 third joint, which it just equals in length ; flagellum uniarticulate, short and conical, 

 ending in a tuft of setae. 



The lower antennas (rv. L*) are thin, but not much shorter than the upper ; the 

 first joint not distinguishable in the specimen examined, the second and third short, 

 the fourth longer, the fifth rather longer than the fourth, with two long hairs near the 

 end ; the flagellum consists of one rather long and thin articulation, followed by a 

 minute tufted one. 



