LYSIANASSIDAE S5 



rounded-quadrate (though Schellenberg says the point in his species may be absent) ; 

 pleon segment 4 with distinct basal indentation and a low keel which overlaps the 5th 

 segment in a rather characteristic manner ; telson 

 elongate, at least twice as long as broad, even 

 when pressed flat ; inner ramus of uropod 2 not 

 constricted. The antero-lateral angle of the head 

 seems to be shorter and more quadrate (Schellen- 

 berg gives no figure) ; in this respect these speci- 

 mens are more like cicadoides Stebb. (1888, pi. v), 

 but from this species they are easily distinguished 

 by the postero-inferior angle of pleon segment 3 . 

 Side-plate 1 is neither narrowed distally as in 



cicadopsis nor widened as in cicadoides (loc. cit., „ . , . . 



( . . rig. 20. Imetonyx longitelson,n.sp. a. Anterior 



pi. iv), but parallel-sided, rounded below. margin of head with antenna t> epistome and 



The telson and absence of Strong upstanding upper lip. b. Pleon segments 3-6 and telson. 



spines on the outer plate of the maxilliped c - Telson. 



distinguishes this species from miersi Stebb. 

 All the specimens are pale creamy in colour, and there is no trace of eyes. 



Tmetonyx carinata (Schell.) 



Schellenberg, 1926, p. 271, fig. 18 (Tryphosa c). 



Occurrence: St. 170. South Shetlands. 1 (J 16 mm. 



Remarks. The triangular process on the upper lip, the character of the 1st gnathopod 

 (simple in $, feebly subchelate in $, and with a strong tooth on inner margin of finger), 

 and the 2nd maxilla seem to indicate that this species would be better placed in the 

 present genus. 



It should be compared with the type of T. stebbingi (Wlkr.), the upper lip of which is 

 undescribed. 



Distribution. 'Gauss' winter station, 385 m. 



Genus Katius, Chevr. 



Chevreux, 1905 {Bull. Inst, ocean. Monaco, no. 35), p. 1. 

 Stebbing, 1906, pp. xxi, 721. 

 Schellenberg, 1927, p. 681. 



This genus was originally placed near Orchomenopsis and occupies a similar position 

 in the works of Stebbing, Stephensen (1925) and Schellenberg. It seems remarkable 

 that no one has commented upon its extraordinary resemblance to Eurythenes. In face 

 of the acceptance of the genus by all authorities it may seem bold to ask what are the 

 characters on which Katius is separated from Eurythenes and to question the validity of 

 these characters for generic purposes. 



A comparison of the descriptions and figures given by Chevreux, Sars (1895, p. 85, 

 pi. xxx) and Schellenberg (1927) shows the following differences: Katius has a less 



