408 Annals of the South African Museum. 



DYNOIDES SERRATISINUS, n. sp. 

 (Plate XXXIV. F.) 



Body parallel-sided, rather strongly convex, minutely granulate 

 and finely setulose, the setules being thickest on the epimera. Head 

 and peraeon smooth, without any trace of tubercles, 7th segment of 

 peraeon bordered laterally by the epimera of 6th segment, epimera 

 rather long, quadrate. Pleon segments 1-4 so intimately fused that 

 sutures are invisible. From the posterior margin arises a large, 

 triangular, conical process extending to middle of telson, its basal 

 width equal to half that of the segment. Telson strongly convex in 

 centre, where it is covered with scattered granules (stronger than 

 those on the rest of body), near the margins and especially at the 

 apex, it is flat, apex pointed, with a deep parallel-sided slit whose 

 anterior end has a small triangular median lobe and whose sides are 

 furnished with 7 backwardly-directed acute teeth. The median lobe 

 and the outer distal margins are setulose. 



First antenna reaching to middle of 1st peraeon segment, 1st joint 

 equal to 2nd and 3rd together, 3rd a little longer than 2nd, flagellum 

 as long as peduncle, 13-jointed, 1st joint equal to 3rd peduncular 

 joint. 



Second antenna reaching to beginning of 2nd peraeon segment, 

 1st and 4th joints subequal, 3rd shortest, 5th longest, 2nd inter- 

 mediate in length between 4th and 5th, flagellum longer than 

 peduncle, 20-jointed, the joints strongly setose. 



Epistome, distance from proximal margin to base of upper lip less 

 than width across the arms, proximal end rounded, sides very slightly 

 concave, distal margin of upper lip rounded setose. 



Lower lip, lobes oval, apically subacute, strongly setose. 



Mandible, trunk straight, somewhat stout, cutting-edge 4-dentate, 

 secondary cutting-edge in left 3-dentate, spine-row with 5 spines in 

 left, 6 in right, molar quadrate, strongly denticulate and setose on 

 posterior margin, palp with 1st joint stout, 2nd and 3rd slender, 1st 

 and 2nd subequal in length, 3rd a little longer, 2 long setae on apex 

 of 2nd, margin of 3rd with gradually lengthening setae. 



First maxilla, outer plate with 6 spines. 



Second maxilla, outer and middle plates with 4 spines, the 2 largest 

 denticulate, all three plates subequal in width. 



Maxilliped, 2nd joint 3 times as long as broad, 4th, 5th and 6th 

 joints lobed internally, 6th not so strongly as the other two, inner 

 plate half the length of 2nd joint, apex rounded with plumose setae, 

 1 coupling-hook. 



