336 Annals of the South African Museum. 



dorsal constriction of the 5th peraeou segment is peculiar, though 

 foreshadowed by the longitudinal groove, more or less broad, in 

 certain other species, notably G. dentata Sars and abyssorum Sars ; 

 but in no other species does the 6th segment approach the 4th. 



GNATHIA sp. 



Female. Body not quite twice as long as broad. Head with 

 rounded entire anterior margin. The lateral margins of the head 

 show a slight bulging in the place where the eye should be, but there 

 is no trace of pigment or corneal lenses. 

 Antennae as described for Larva 1. 



Maxilliped, inner distal angle of 2nd joint acutely produced, 4th 

 joint of palp not incurved. 



Peraeopocl 1 apparently only 1-joiuted, the sutures between the 

 normal 3 joints being impossible to trace. 



Telson much longer than its basal width, sides slightly concave, 

 apex subacute, with 2 setae. 



Larva 1. 4 mm. x '75 mm. Head triangular, broader at base 

 than long, lateral margin straight, autero-lateral angles excavated for 

 the insertion of the antennae, front margin truncate between the 

 antennae. No trace of eyes. 

 Telson as in 9 



Head, pleou and all the parts of the peraeon which are strongly 

 chitinised are covered with little specks more opaque than the rest of 

 the integument. 



Peraeon segments 2 and 3 subequal ; 4th chitinised laterally and in 

 the middle, where there is a large rounded plate; 5th chitiuised 

 laterally only ; 6th chitinised nearly for the whole width but not on 

 the anterior margin. 



Antennae not much longer than greatest width of head, in antenna 1 

 3rd joint longest, flagellum 5-jointed, 1st very short, 2nd longest ; 

 in antenna 2 5th joint considerably longer than 4th, flagellum 

 5-jointed. 



Labrum long, ovoid, apex emarginate. 



Larva 2. 5 x 1 mm. Similar to the last but more swollen. 

 Larva 3. 5 x 1'5 mm. Similar, but the antennae are here twice 

 as long as the greatest width of the head, the joints proportionately 

 the same in length, though more slender. Peraeopod 1, 3rd and 4th 

 joints subequal, 6th longest, unguis strong and curved, no recurved 

 denticles or serrations. 



Length : $ 5 mm. ; breadth : 3 mm. 



