36 ATLAS OF BIOLOGY. 



XII. The second maxilla. 



XTIL The first maxilla. 



The coxopodite of this appendage is carried, during life, inserted into the mouth. 



(Compare Plate IX., Fig. V.) 



XIV. The mandible. 



The endopodite of- the second maxilla, Fig. XII., en, is carried, during life, hooked 

 over the recess marked*. 



XV. The antenna. 



XVI. The antennule. 



XVII. The eye-stalk. 



XVIII. The third abdominal appendage of the ? , taken as a type of that series. 



XIX. The second abdominal appendage of the <?. 



XX. The first abdominal appendage of the 3 . 



XXI. The same of the ? . 



This limb varies very much in size in different individuals ; the extremes observed are 

 indicated by the two lines drawn to the left. 



XXII. The last abdominal appendage. 



FIG. XXIII. The three terminal joints of the right chela, laid open, to display their 

 muscles. 



The dotted lines indicate the positions of the underlying tendons. Nat. size. 



FIG. XXIV. Longitudinal section of the whole animal, all the soft parts having been 

 removed, with the exception of the muscles. 



Portions of the great gastric muscles (compare Fig. VII., Plate IX.) and of those 

 connected with the basal joints of the chela, antenna, and mandible, have been left. Nat. 

 size. 



This dissection is best performed upon an animal previously hardened in alcohol. 



