new Commensal Praion. 133 



afj^ain as stalk, outer flacrpllum very slii;"liily loiifjer tlian 

 inner, its thickened part rather more than a thii'd of its whole 

 length, cleft less than halfway ; antennal scale broad, con- 

 siderably outreaching antennular stalk, rather acutely pointed, 

 with the spine of the outer edge set back about a quarter of 

 the length from the end, antennal stalk reaching end of first 

 joint of antennular ; second and third maxillipeds without 

 exopodites ; third maxillipeds moderately slender, reaching a 

 little beyond origin of antennal scale ; legs of first pair 

 a little outreaching antennal scale, with wrist very slightly 

 shorter than hand, and fingers straight, simple, sharp-edged, 

 and sharp-pointed, bearing a few bristles at the end ; legs of 

 second pair unequal, the larger reaching nearly as far as the 

 antennular flagella, with long, almost rectangular palm, a 

 little swollen towards the base, simple fingers, not quite half 

 length of palm, bearing a few hairs at the tips, wrist simple, 

 unarmed, about half length of fingers, arm simple, unarmed, 

 about three-quarters length of palm ; walking-legs stout, sub- 

 equal, the first pair reaching nearly to the end of the first 

 chelipeds, unarmed save for a movable spine near end of 

 each propodite and some stout bristles, with a swelling on the 

 underside of the meropodite near its distal end, and a slight 

 projection of the base of the dactylopodite, which is short, 

 stout, and rather strongly hooked ; sixth abdominal segment 

 longer than fourth and fifth together, about as long as telson ; 

 endopodites of uropods a little longer than telson, shorter tiian 

 exopodites ; telson tapering, truncate, with the intermediate 

 pair of terminal spines very strong. 



Colour in life " almost transparent except the ovigerous 

 females, which are pigmented according to the gorgonian on 

 which tliey live, orange, lemon-yellow, or almost red." 



Length "5— '7 mm. 



Type-specimens in the U.S. National Museum. 



TliQ affinities of the species are not very clear. Its 

 simplicity of form and the almost complete absence of spines 

 from its rostrum, trunk, and limbs seem to point to a rela- 

 tionship with P. aurantiaous (Dana), 1852, and, if this 

 suspicion be confirmed, we have in P. heaufortensis a second 

 member of the subgenus /'r«.«/'/<'>' ; hut until more is known 

 about P. mirantiacus nothing can Idg said with confidence upon 

 the subject. 



