GENERAL BIOLOGY 



(2) probably correspond to the protopodite of the abdominal ap- 

 pendages, and the other five to the endopodite, as may be seen by 

 comparing all of the other appendages with the third maxilliped. 



b. The next pair of appendages have in addition a branchia 

 and epipodite upon the coxopodite extending up into the branchial 

 chamber. 



c. The third and fourth appendages (counting forward) differ 

 in having the propodite produced opposite the dactylopodite to 

 form a pair of forceps. 



d. In the large anterior pair of ambulatory appendages, the 

 chelae, the forceps is greatly enlarged and the basipodite and ischio- 

 podite are united into one piece. 



e. The third or posterior maxilliped should be carefully studied. 

 Note: (i) The large basal part, protopodite, bears a long five 

 jointed endopodite and a slender many jointed external expedite, 

 besides a curved lamella, epipodite, lying in the branchial chamber 

 and bearing a branchia. (2) The protopodites and endopodites 

 make up together a seven jointed organ like the ambulatory ap- 

 pendages. 



f. The second maxilliped differs from the last mentioned, 

 chiefly in the size of the endopodite. 



g. In the first maxilliped the endopodite is short and flat, the 

 protopodite two jointed and foliaceous, the epipodite has no gill. 



III. CEPHALIC APPENDAGES. 



These are the maxillae, mandibles and antennae. 



(a) Second or post maxillae; the endopodite is not jointed, while 

 the two parts of the protopodite are subdivided or cleft ; the large 

 oval plate, scaphognathite, acting to bail water out of the branchial 

 chamber, represents the epipodite and probably also the exopodite. 



(b) First maxilla; this is very small and lies close to the mandible. 

 It is divided into three parts representing the coxopodite, basipodite 

 and endopodite. (c) Mandibles ; each has a strong basal part bear- 

 ing a two jointed palp or endopodite. (d) Post antenna (antenna 

 proper) ; each has a two jointed protopodite with the opening of 

 the green glands on a tubercle on the proximal joint, the scale-like 

 plate is the exopodite and the long, filiform, many jointed part is 

 the endopodite. (e) First antenna (antennula) ; here the pro- 

 topodite has three joints and bears a long many jointed endopodite, 

 and a similar exopodite, while upon its large proximal joint is the 

 opening of the auditory organ, surrounded by hairs. 



[57] 



