124 



Platyischnopus. Haustorius 



distally to a small tooth, forming a little chela with tlie minute fiuger. 

 Peraeopod 1, ()^^ Joint rather longer than 5*^ apex oblique with about 

 () spiuiform setae, a little longer and more sleuder thau the finger. Peraeo- 

 pod 2 rather longer than peraeopod 1, 5*^ Joint with convex bind margin, 

 canTing about 6 pluraose setae, which reach beyond the ünger. Peraeopod 3, 

 2^ Joint as broad as long, remainder not very different from P. mii-abilis. 

 Peraeopod 4 similar to peraeopod 3. Peraeopod 5, 2^ Joint broader than 

 long, 4*^ and 5*^^ moderately expanded. Uropod 3, peduncle much shorter 

 tlian rami, outer slightly longer, 2-jointed, each with 2 or 3 long plumose 

 setae. Telson double or deeply cleft, each lobe with 2 lateral setules and 

 a stout apical spiue. L. about 4 mm. 

 Otago Harboiir [New Zealandj. 



3. Gen. Haustorius St. Müll. 



1775 Haustorius (Sp. un.: H. arcnarhis). St. Müller in: Slabber, Phjs. Belustig., 

 p.48 I 1888 H., T. Stebbing in: Rep.Voy. Challenger, f. 29 p. 39 ,' 1891 H., G. 0. Sars, 

 Crust. Norway, v.l p.l34 1 1893 H., A. Della Valle in: F. FI. Neapel, ».20 p. 750 j 1818 

 Lepidactylis (Sp. un.: L. dytiscus), Say in: J. Ac. Philad., ulii p.379 | 1825 Pterygocenis 

 (■Sp. un.: OniscHS arenarius), Latreille in: Enc. metli.. f. 10 p. 236 j 1829 Fterygocera, 

 Latreille in: G. Cuvier, Regne an., n. ed. vA p. 124 | 1851 Bellia (Sp. un. : B. arenaria) 

 (non H. Milne Edwards 1848, Decapoda!), Bäte in: Ann. nat. Hist., ser. 2 v.l p. 318 j 

 1854 Sulcator, Bäte in: Ann. nat. Hist., ser. 2 r. 13 p. 504. 



Back broad, except in pleon segments 4 — G, which are usually folded 

 in. Head with small rostrum. Side-plates 1 — 3 obtusely pointed, 4^^^ little 



Accessoi-y 

 flageUum 



Inner 

 plate 



Fig. 32. Antennai. Fig. 33. Antemia 2. Fig. 34. Maxilla 2. 



Fig. 32—34. H. arenarius. [After G. 0. Sars.] 



excavate. Autennae 1 and 2 (Fig. 32, 33), joiuts of peduncle very distinct, 

 with fan-like armature of plumose setae chiefly ou penultimate, flagellum 



shoiter than peduncle; accessory flagellum of 

 antenua 1 well developed; penultimate Joint of 

 peduncle of antenna 2 longer and greatly wider 

 than ultimate. Mandible normal, palp large, 

 3<^ Joint not shorter than 2^. Maxilla 1, inner 

 plate small, with several setae, outer apically 

 narrowed, palp with 2 sets of setae on 2*^ Joint. 

 Below the base is a setose lamiua, of which 

 6">jonit ^j^g homology and function have not hitherto 

 been explained. Maxilla 2 (Fig. 34), inner 

 Fig. 35. H. arenarius. plate with a sinuous setose ridge on the 



Peraeopod 4. [After G. 0. Sars.] surface, outer much larger, semilunar, densely 



setose on inner and ciliated on outer margin. Maxillipeds, inner and outer 

 plates subequal, naiTow, fringed on inner margin, 2'^ Joint of palp large, 



