A MANUAL OF ZOOLOGY 19 



what kind of a joint? Note any differences in the different 

 segments. On what abdominal segments are appendages 

 (swimmerets) found? Note the tergum, the dorsal por- 

 tion of a segment; the sternum, the ventral portion; the 

 epimeron, the latero-ventral portion; the pleuron, the down 

 growth of the sides. Note the parfs of an appendage; the 

 basal portion, the protopodite; the portion attached to the 

 outer margin of the protopodite, the exopodite; that part 

 attached to the inner margin, the endopodite. Make a draw- 

 ing to represent a lateral view of a segment with its'ap- 

 penoages. ■ 



Describe the cephalothorax from above and from the 

 side. Are there any traces of segments? The cervical 

 groove divides this region into a cephalic and a thoracic 

 region. The branchio-cardiac grooves extend backward 

 from the cervical groove. The heart lies under that por- 

 tion of the carapace bounded by these grooves. Note the 

 rostrum projecting in front. Describe it as to motion, 

 appendages, size, and color. Examine the ventral surface 

 of the cephalothorax. Are there any evidences of seg- 

 mentation? With scalpel handle force out the margin of 

 the carapace, the brclnchiostegite, and notice a chamber 

 here called the branchial chamber, or gill cavity. Is there 

 any suggestion here of segmentation? Compare with -a 

 single segment in the abdomen. 



The last segment of the body is known as the teison. 

 Describe and draw it after observing_a3 to its append agear 

 form,~etc. ^"Note the anal opening on the ventral side. 

 Beginning with the posterior pair of appendages disartic- 

 ulate them on the right side of the abdomen, by cutting 

 through the articular membrane with a sharp scalpel. 

 This will require care in order to get them clear from the 

 body and also entire. Study ea«h appendage and note 

 all the palrts referred to above. In addition note that the 

 protopodite consists of two segments: the coxopodite, the 

 basal portion; the baslpodite, the' distal portion. What 



makes up the tail fin? My tha-appandaffnc-jlnwn ir} nrr|flr 



with their posterior facejippermo st and mak e drawin gs- 

 of same Numbering Ttheiri "In order j)t segments^ Remove 

 the thoracic appendages in like manner, but study them 

 as you proceed. Examine the last thoracic appendage and 



