82 Invertebrate Zoology. 



present. The flabellum is indurated by a deposit of lime and 

 stiffened by its fusion with the exopodite. What is the 

 probable function of this the most anterior flabellum ? The 

 endopodite resembles the same of the first maxilliped. The 

 protopodite is divided into four long inwardly-projecting 

 lobes. 



Draw. 



After identifying the parts of the first maxilla, draw and 

 name, taking care not to be confused by the fan-like out- 

 growths of the lowef lip. 



The body of each mandible represents the protopodite, 

 while the palpus represents the endopodite. 



Draw as seen from in front, naming the parts. 



The second antenna presents a modification of the same 

 double structure that has been noted in the other appen- 

 dages. The protopodite bears an exopodite, a mere mov- 

 able scale, and a much elongated endopodite, which func- 

 tions as a tactile organ. 



Draw. 



The first antenna, the antennule, is in the adult also bira- 

 mous, though primitively it is uniramous. 



Draw. 



Morphology of the Carapace It has probably been 

 noted that a transverse groove divides the anterior portion 

 of the cephalothorax from the posterior. The carapace, 

 then, probably represents the fusion of terga, and our prob- 

 lem is to find out which have become fused. 



If the groove be followed ventrally and anteriorly, it will 

 lead to a septum between the second antennae and the man- 

 dibles. It is probable, then, that the groove marks the 

 dividing line between these two segments, second antennal 



