80 ZOOLOGY DIREC TIONS 



indicates that the structure is present, a zero that it is wanting. 



segment appendage exopodite endopodite protopodite epipodite gills 



prostomium antennules + -f- 



I. antennae + + + 



II. mandibles + + 



III. 1st maxillae + + 



IV. 2nd maxillae + + + + 



9. On your note paper prepare a table for the thorax and 

 abdomen, using the same column headings as above. Data for 

 filling out this table will be secured, in the course of the study 

 and should be incorporated into the table only after the study 

 has been made as directed and after drawings that are asked for 

 have been prepared. The thorax includes segments V to XII 

 and bears three pairs of maxillipeds and five pairs of walking 

 legs. The abdomen comprises segments XIII to XVIII and 

 the telson. 



10. In the same manner as directed above study the third 

 maxilliped which lies immediately anterior to the cheliped. Ex- 

 amine carefully while still in place, to make sure of proper ar- 

 rangement of parts, then remove and draw ventral view, X4 

 Distinguish protopodite (made up of coxopodite and hasipodite) , 

 exopodite, endopodite, epipodite, and gills. 



11. Remove, study, and draw second maxilliped. Continue 

 the study, using the first maxilliped. Draw. Do you find gills 

 on each of these ? 



12. The second maxilla has a broad, thin protopodite near 

 the median line of the body. The exopodite is fused at its poster- 

 ior extremity with the epipodite to form a tough, membranous 

 structure, the gill hailer. The endopodite is a very minute pro- 

 jection between protopodite and exopodite. Draw. 



13. The first maxilla consists of only two conspicuous, flat- 

 tened lobes, the outer one of which is the endopodite and the 

 other the protopodite. Draw. 



14. All the hard part of the mandiMe and the basal joint 



