BORRADAILE— ON THE PONTONIIN^ 347 



y8. Eyes not subspherical. Rostrum vertically expanded. 



(1) Body and chelipeds Pal(Bmon-like. Dactylopodites of walking legs 



usually narrow. 



Periclimenes Costa, 1844. 



(2) Cephalothorax deep and flat-sided, recalling Alpheus. One of 



second chelae very heavy, with short fingers bearing a knob and 

 socket arrangement. Dactylopodites short, broad, and biungui- 

 culate. 



PericUmencBUS Borradaile, 1915. 



ii. Clumsy-bodied forms, with body obviously depressed, at least in female, 

 rostrum usually in some way reduced and often toothless, stout legs, 

 ending in short, usually hooked dactylopodites, and antepenultimate 

 joint of third maxilliped moderately or very broad. 



a. Rostrum straight or upcurved, diminishing in normal fashion to a 

 sharp point, usually toothed, but generally with little or no ventral 

 crest. Body not very clumsy. Third maxilliped not strongly 

 twisted. 



(1) Dactylopodites of walking legs without basal protuberance. Last 



two joints of third maxilliped narrow and usually contrast 

 strongly in width with antepenultimate. 



(a) Third maxilliped with arthrobranch. Second maxilliped with 

 last joint mediad of penultimate. 

 Harpiliopsis n. gen. 



(h) Third maxilliped without arthrobranch. Second maxilliped with 

 last joint posterior (distal) to penultimate. 

 Harpilius Dana, 1852. 



(2) Dactylopodites of walking legs bear a basal protuberance, usually 



large. Last two joints of third maxilliped do not contrast 

 strongly in width with antepenultimate, and are usually broad. 



{a) Rostrum not very broad. Basal protuberances of the dactylo- 

 podites simple. 



(i) Rostrum very long. Enormous supraocular spines present. 

 Abdomen carinate. 



Coutierea Nobili, 1902. 



(ii) Rostrum not very long. Supraocular spines absent or not 

 very large. Abdomen not carinate. 

 Coralliocaris Stimpson, 1860. 



ih) Rostrum very broad. Basal protuberances of dactyles paired. 

 Stegopontonia Nobili, 1906. 



44—2 



