MARINE GAMMARIDEAN AMPHIPODA 249 



haustoriids lack a distinct rostrum. All phoxocephalids have pereopod 

 5 shorter than 4 and of different structure, and a large visor-like 

 rostrum. Some haustoriids have a small rostrum and pereopod 5 

 shorter than 4 and of different structure. With some genera, one 

 must flip a coin to choose the proper family. 



Figure 97. — Haustoriidae: a, Priscillina armata (Boeck) (Sars, 1895, pi. 42); b, Urothoe 

 elegans Bate (Sars, 1895, pi. 47, as U. norvegica). Upper lip: c, Haustorius arenarius 

 (Slabber) (Sars, 1895, pi. 46). Mandible: d, Urothoe; e, Haustorius; f, Carangolia mandi- 

 bularis J. L. Barnard (1962d). Lower lip: g, Haustorius; h, Pontoporeia femorata Kr^yer 

 (Sars, 1895, pi. 41). 



