200 ELEMENTARY BIOLOGY. [CHAP. 



during life, is received into a recess of the mandible. 

 Its epipodite; well developed, and united in front 

 with a lamina, which probably represents the exopo- 

 dite, to form a wide oval plate (scaphognathite) which 

 lies at the anterior end of the gill-chamber (Cf. 

 Sect. H. c. and p. 182). 



If the above appendage be examined in the living 

 animal, it will be found that with every movement 

 of the scaphognathite there is a corresponding pull 

 upon its filamentous endopodite. 



/. The first maxilla. Epipodite and exopodite un- 

 developed. The endopodite is reduced to the 

 condition of a small squame, its basal segment 

 (ischiopodite) being enlarged and foliaceous 1 con- 

 stituting the main mass of the whole appendage. 

 Its protopodite is foliaceous and single jointed 

 (basipodite), blade-like and recurved, with its free 

 end inserted, during life, into the oral aperture. 

 (Cf. Sect. E. 6 d.) 



In the Lobster, the endopodite is large and seg- 

 mented. 



k. The mandible. Its strong toothed basal -joint (cox- 

 opodite) bearing a small appendage (the palp} which 

 represents the basipodite and endopodite 1 , epipo- 

 dite and exopodite unrepresented. 



/. The antenna. Its two-jointed basal-portion (pro- 

 topodite) bearing a flattened protective squame (the 

 modified exopodite) and a long multi-articulate 

 filament (the endopodite), the two basal segments of 

 which are greatly enlarged and modified for pur- 

 poses of articulation. Note the opening of the 

 green gland (Cf. Sect. A. c. 8). 



1 As is seen on comparison with the same in certain of the lower 

 Crustacea. 



