2o6 ANNUL AT A. 



part of the exterior partially shut in. In many Crustacea 

 the part of the body here covered by the carapace is divided 

 into head and thorax^ and in Nephrops the line of junction 

 is shown by a cervical suture passing down laterally and 

 obliquely from the mid-dorsal line. 



Fig. 130. — Lateral View of Norway Lobster (Right) x |. 

 (Ad nat.) 



Branchial Cervical 



ist Abdominal Segment. Plate. Suture. Eye. 



\ ; i T Rostrum. 





\^., 



Chela. 



, / Swimmeret. 3rd Maxillipede. 



I Telson. ,, , t 



6th Abdominal Segment. '' " ist i.eg. 



The third portion of the body, behind the carapace, i; 

 called the abdomen. In this region there are severa 

 sclerites movable on each other and they are found tc 

 correspond with the metameric segments of the body 

 Each abdominal sclerite is roughly in the form of a ring 

 The dorsal part is called the tergon, the ventral narrov 

 part is the sternon, and from the junction there hangs dowr' 

 laterally the pleuron. Just inside the pleuron there is at 

 appendage on each side. Each abdominal sclerite i: 

 fastened to its fellows in front and behind by dorsal anc 

 ventral arthrodial membranes and laterally by a pair of baU | 

 and-socket joints, which allow of movement only arounc 

 the axis through them. The sclerites overlap dorsally thosd 

 behind them. The last (7th) abdominal sclerite is flattenec 

 and bears no appendages : it is called the telson. The appen 

 dages of the abdominal sclerites are termed swimmerets fo; 

 they are mainly used for swimming. They consist typicall;: 

 of a basal piece, tht protopodiie, bearing two paddles, the oute 



