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angle with a large laterally directed spine. Second and third somites 

 similar, each with triangulate anterolateral extensions and a trans- 

 verse row of four large spines on dorsal surface. Fourth somite ex- 

 ceeding tvfo times the length of third, having spination of third 

 somite plus a single small spine on middorsal surface at posterior 

 border; epimeral spine visible in dorsal view below anterolateral 

 spine. Fifth and sixth somites similar to but narrower than third 



Figure 17. — Idarcturus hedgpethi, new species; a, Dorsal view, holotype; b, maxilliped; c, 

 first pleopod, magnification not known; d, right mandible; e, fifth peraeopod. (Magni- 

 fication as indicated by scales.) 



