188 HANDBOOK OF INVERTEBRATE ZOOLOGY. 



{. The fourth and fifth abdominal segments closely 

 resemble the third. 



j. The appendages or swimmerets of the sixth abdomi- 

 nal segment are very large, and are made up of — 



1. A protopodite, which consists of a single, short, 

 strong joint. 



2. A wide exopodite, fringed with long hairs, and 

 divided into two portions by a transverse joint. 



3. A triangular endopodite, also fringed with long hairs. 

 h. Make a sketch of this appendage. 



I. The second abdominal segment of the female is much 

 like the third, and carries a pair of ordinary pleopods, 

 and the appendages of the first abdominal segment of the 

 female are rudimentary. 



m. In the male, the protopodite and endopodite of the 

 appendage of the second abdominal segment are elongated 

 and rolled up so as to form an imperfect tube. 



n. The first abdominal a})pendage of the male is a sin- 

 gle plate, rolled into a tube, and lying in the groove upon 

 the second appendage. 



0. The terga of all the segments anterior to the first 

 abdominal, are represented, or at least replaced by, the 

 carapace, which is made up of a median dorsal area, and 

 two lateral folds, or branchiostegites^ which lie above the 

 bases of the pereiopods. Raise up the margin of this 

 fold, and notice the branchial cavity which lies below it. 

 Carefully cut away the fold from one side of the body, 

 and notice the plume-like gills. 



p. Examine and remove the remaining appendages 

 from one side of the body, in the order in which they are 

 described, and place them in their natural order for exam- 

 ination. 



1. The walking legs, or pereiopods, are made up of 



