36 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL.21 



2b. Male abdomen not terminally broadened, seventh segment 

 subtriangular and not inserted deeply into sixth segment. 

 Male first pleopod exceedingly varied, but not as in la 

 3a. Eyes without orbits; eyestalks generally long, either 

 non-retractile, or retractile against the sides of the 

 carapace, or against an acute postocular spine affording 

 no concealment. Basal antennal article extremely 

 slender and usually long .... Inachinae 

 3b. Eyes with incomplete or commencing orbits. Basal 

 antennal article not extremely slender 

 4a. Eyes without true orbits, lacking a postocular cup 

 5a. Eyestalks long; orbit partially protected by a 

 hornlike supraocular spine or by a jagged 

 postocular tooth, or by both. Body often trun- 

 cate in front .... Ophthalmiinae 

 5b. Eyestalks short, little movable, and either con- 

 cealed by a supraocular spine, or sunk in the 

 sides of the rostrum. Basal antennal article 

 truncate-triangular . . Acanthonychinae 

 4b. Eyes with commencing orbits having, in addition to 

 the supraocular spine, a large, cupped postocular 

 process into which the eye retracts. Eyestalks short 

 Pisinae 1 



lb. Eyes with nearly complete or complete orbits. Basal antennal 



article very broad 



6a. Basal antennal article not specially expanded to form a floor 

 to the orbit, which is formed by a supraocular hood, an inter- 

 calated spine, and a postocular cup . . Majinae, s. restr. 



6b. Basal antennal article expanded to form a floor to the orbit, 

 which is formed by the aforementioned spines, although the 

 intercalated spine may be present or absent . Mithracinae 1 



Subfamily INACHINAE 



Inachinae Alcock, 1895, pp. 160, 162, 168. Rathbun, 1925, p. 11. Balss, 



1929, p. 3. 

 Inachidae Stebbing, 1910, p. 283. 



'The further division of the Pisinae into Pisinae, sensu restr., and Hyasteniinae, 

 and of the Mithracinae into Mithracinae proper and Macrocoelominae according 

 to the presence or absence of the intercalated spine, as proposed by Balss (1929), 

 is not here adopted. 



