LYSIANASSIDAE 6 S 



Schellenberg states that Allogaussia is near Orchomenella though he places it far away 

 in his Gauss Report. He also refers to the likeness and possible identity of his A. 

 litoralis (p. 249) with Orchomenella franklini, Wlkr. The relationship between both of 

 Walker's species, pinguides and franklini, and the species of Allogaussia seem to be very 

 close, and it is difficult to decide without material of the northern species for com- 

 parison whether the former have been rightly referred to Orchomenella. Sars' figures 

 of O. minuta and pinguis (1895, pi. xxiv, figs. 1 and 2), but not of ciliata (= nanus) and 

 groenlandica (pi. xxv, fig. 2 and pi. xxvi, fig. 1), nor Bonnier's figures of laevis, show a 

 very definite posterior lobe on the 5th side-plate and also a narrow projecting lobe on 

 the 4th side-plate. Walker's figures of franklini (1903, pi. viii, figs. 31 and 35) show the 

 same features and likewise the two species here described. 



But in the northern species the 2nd joint of peraeopod 3, though it appears (Sars, 

 pi. xxiv, fig. 1, p 5 .) to be confined within the 5th side-plate, is not particularly 

 expanded. Of what generic value are these characters? 



The epistome in the original species of Allogaussia and of the two here included is 

 not greatly different from that of the typical species of Orchomenella. The epistome of 

 Walker's two species is undescribed. 1 If pinguides and franklini be included in Allo- 

 gaussia on account of peraeopod 3, then the form of telson ceases to be of generic 

 importance, as there are both the short entire form (paradoxa) and the long form which 

 may be either notched (naviada) or shallowly (litoralis) or deeply (pinguides and lobata) 

 cleft. 



Further work on the points here raised is required, including a comparison of the 

 northern and southern species of Orchomenella. 



Allogaussia navicula, n.sp. (Fig. 25). 



Occurrence: 1. St. 170. South S'letlands. 3 <$£, 4 ?? 7-8 mm. 



2. St. 175. South Shetlands. 2 <$£ 8 mm., 2 ?$ 8-9 mm. Types. 



Description. Integument indurated, with scattered punctae. Body distinctly plumper 

 in $ than in <$. Head with antero-lateral angle quadrate, but the actual angle rounded. 

 Eyes large, narrow above, widening below, pale brown or reddish. Peraeon dorsally 

 rounded. Side-plates deep, 1-3 oblong, rounded below, more so in 1 than in 3 ; 

 4 narrow, with long but rather shallow excavation, the posterior projection narrow, 

 rounded, fitting into a slight groove on 5, which is ovate, deeper than long with a 

 distinct posterior lobe but no anterior lobe; 6 oblong, the posterior lobe distinct; 

 7 deeper than long, rounded below. Pleon dorsally rounded, except for a low rounded 

 medio-dorsal keel on segment 4 and 2 dorso-lateral keels on segment 6 projecting as two 

 short rounded lobes on either side of telson ; postero-inferior angle of segment 1 rounded, 

 of 2 quadrate, of 3 rounded-quadrate, margin entire. Telson oblong, twice as long as 

 broad, slightly tapering, deeply concave dorsally like a gouge chisel, extending to about 



1 In the Nimrod specimens of pinguides and franklini recorded in the Terra Nova Report (1930, p. 448), 

 which certainly seem to agree with Walker's descriptions and figures, the epistome forms a strongly pro- 

 jecting lamina, and side-plate 4 does not fit into a groove in side-plate 5. 



