348 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 21 



2b. Orbits projecting laterally somewhat beyond the general 

 outline of the carapace 



5a. Rostrum small. Carapace ovate, usually broader than 

 long 



6a. Lateral margins of carapace laminiform, coarsely 



dentate. Chelipeds and legs cristate above. Orbital 



margin not incised, bearing a preocular spine and 



a postocular tooth . Ala [ = Anaptychus] 



6b. Lateral margins armed with four, or three, spines 



or lobes behind orbit. Legs spinous. Orbital margin 



spinous or tuberculous . . . Mithrax 



5b. Rostrum of good size, usually with two strong horns. 



Carapace broadly pyriform. Basal antennal article 



armed with a prominent spine at anteroexternal angle 



Microphrys 



lb. Intercalated spine absent ; orbits tubular 



(Macrocoelominae Balss) 



7a. Lateral margin of carapace armed with a series of strong 

 spines. Basal antennal article very broad 

 8a. Basal antennal article quadridentate. Postocular tooth 

 large, quadrangular, armed with two teeth or spines 



Coelocerus 



8b. Basal antennal article with fewer than four spines or 

 teeth. Postocular tooth of moderate size, triangular, 

 armed with only one spine . . Stenocionops 

 7b. Lateral margin of carapace not armed with a series of 

 strong spines, but with a spine, usually strong, at the lat- 

 eral angle of the carapace 



9a. Orbits strongly projecting. Rostral horns short. Cara- 

 pace broad Macrocoeloma 



9b. Orbits little projecting. Rostral horns long and slen- 

 der. Carapace narrow .... Leptopisa 



Genus ALA Lockington 



Anaptychus Stimpson, 1860b, p. 183; type: A. cornutus Stimpson, 1860, 

 by monotypy. A. Milne Edwards, 1875, p. 66. Rathbun, 1925, p. 

 377. Not Anaptychus Oppel, 1856. 



Ala Lockington, 1877c, p. 65; type: A. spinosa Lockington, 1877, by 

 monotypy. Balss, 1929, p. 16. 



