SYSTEMATIC ACCOUNT 177 



general body surface. Each pair is separated by a median space (Text-fig. 15 a). These protuberances 

 decrease in size and height from the fourth pair backwards ; the series is continued on to the pleotelson 

 where it is represented by three pairs of rounded tubercles. A further series of these raised areas 

 occurs in a lateral position above the coxae of the limbs of each pereion somite except the first; 

 a smaller pair is present on the pleotelson in front of the articulation of the uropods. The body 

 surface between the median and lateral protuberances is itself slightly raised and this is more marked 

 on the last three somites. The third pereion somite is the broadest, but this width is much greater in 

 the female than in the male; in the latter there is only a very gradual decrease in width from this 

 somite to the last one. 



The abdominal segments are fused together to form a pleotelson which forms about one-third of the 

 length of the body. The three pairs of tubercles may possibly indicate the position of three fused 

 segments. The convex surface of the pleotelson slopes away sharply a short distance behind the last 

 pair of tubercles; it ends in a blunt, up-tilted point. 



The antennu/es (Text-fig. 15^) do not extend to the end of the third peduncular joint of the 

 antennae; each consists of a peduncle of three joints and a fiagellum consisting of one large and a 

 terminal minute joint from the extremity of which arises a single sensory seta and a group of three 

 simple ones. The sensory setae on the flagellar joint extend its whole length in the male (Text- 

 fig. 15^), but are restricted to the distal half in the female (Text-fig. 15^). 



The antenna (Text-fig. 15/) is stout and slightly over half of the length of the body. The peduncle 

 consists of five joints, the first two of which are short, the third joint is broad and longer than the 

 first two together ; the fourth and fifth are subequal and about equal to the length of the second and 

 third together. The upper and lateral surfaces of these joints are tuberculate, the ventral margin is 

 fringed with long setae which are directed towards the mouth region. The fiagellum consists of two 

 joints which together measure about half the length of the fifth joint of the peduncle; the terminal 

 joint is about half the length of the basal one and is tipped with a stout curved spine. 



The moiithparts are normal; their form can be seen from Text-fig. 156, ^ and^ and Text-fig. idk 

 and /. 



The coxae of the first pair of pereiopods are fused with their somite, but the suture between the 

 ventrally extended coxal plates may be seen in the mid-ventral line. The coxae of the second, third 

 and fourth pairs of pereiopods are just visible in lateral view; they too are expanded into ventral 

 plates, the sutures between which may be seen in the mid-line. The coxae of the last three pairs of 

 pereiopods are completely fused with their respective somites, and the plates of each pair are fused 

 together in the mid-ventral line. This condition of the coxae and their plates agrees with that found 

 in Pseudidothea bonnieri. 



The first pair of pereiopods (Text-fig. iba) is short, stout and subchelate and is closely applied to 

 the mouthparts. The propodus is broad and armed with modified setae, each of which has a double row 

 of minute rounded serrations; the dactylus ends in one large and two smaller curved spines. The 

 remaining pairs of pereiopods are of approximately the same length except for the last pair which is 

 slightly shorter and more slender. The second, third (Text-fig. 16;) and fourth pairs are directed 

 forwards and differ from the remaining three pairs in having the inner margin of the ischium, merus, 

 carpus and propodus sparsely fringed with long setae. The basipodite of each of the last three pairs 

 (Text-fig. 16/) bears a well-marked conical projection in about the middle of the length of its posterior 

 surface. 



The brood pouch, unlike that of Pseudidothea bonnieri, consists of five instead of four pairs of 

 lamellae, of these the last pair (Text-fig. 16^) is small and forms the posterior limit of the marsupium. 

 The fused ventral coxal plate of the fifth somite in the breeding female is narrow and limited to the 



