HAUSTORIIDAE 



93 



shape of the head, and of the ist and 4th side-plates should be used instead of the 

 4th and 5th peraeopods. 



Urothoides oniscoides, n.sp. (Fig. 45). 



Occurrence: St. 196. South Shetlands. 1 $ with embryos 5 mm. 



Description. Head and body depressed, very broad. Integument thickly covered 

 with minute bristles. Head in dorsal view broader than long, antero-lateral angle 

 rounded quadrate, anterior margin broadly convex; in lateral view very shallow, post- 

 antennal angle obsolete, rostral projection not deflexed. No eyes. Side-plate 1 much 

 expanded below, curving forwards alongside head, 2 and 3 oblong, somewhat curved, 

 lower margins straight, 4 with anterior margin strongly convex, whole hind margin 



Fig. 45. Urothoides oniscoides, n.sp. a. Dorsal view of head, with side-plate 1 in perspective, b. Portion of 

 integument highly magnified, c. Pleon segment 3. d. Gnathopod 1. e. Side-plate 3. /. Side-plate 4 and 

 peraeopod 2. g. Peraeopod 3. /;. Peraeopod 4. i. Peraeopod 5. 



concave. Pleon segment 2 with postero-inferior angle rounded-quadrate, lower margin 

 setose; pleon segment 3 with postero-inferior angle produced in a strong acute point. 

 Segments 4 and 5 short, indistinctly separated. Telson as in lachneessa Stebb. 



Antenna 1, flagellum 5-jointed, accessory flagellum 3-jointed. Antenna 2, flagellum 

 5-jointed. Mouth-parts as in lachneessa; mandibular palp rather longer. 



Gnathopods 1 and 2, and peraeopods 1 and 2 as in lachneessa, but peraeopods 1 and 2 

 rather more slender. Peraeopod 3 as in lachneessa, but 4th and 5th joints not quite so 

 stout. Peraeopod 4, 2nd joint oval, hind margin not concave, rest of limb much longer 

 proportionately, and 4th and 5th joints not more expanded than in Urothoe. Peraeopod 5, 

 2nd joint subcircular, not produced downwards beyond 3rd joint, hind margin 

 serrate with sharp points, rest of limb much longer proportionately than in lachneessa. 

 Uropods 1-3 as in lachneessa. 



