lOO SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I37 



pleuron and the catapleuron. Furthermore, between the latter and the 

 coxa, we have proved the presence of a trochantin certainly homolo- 

 gous with the trochantin of the Orthopteroidea (Carpentier, 1946, 

 1955), but this may be but a derivative of the coxa, in spite of the 

 development and the individualization which it attains in certain 

 orders. 



Now, the question is, do all these formations exist in the Malacos- 

 traca as well, and if so, from what part of the leg do they start in a 

 proximal direction ? 



To take a stand in this matter was to choose between two interpre- 

 tations of the limb base which have been opposed to each other for a 

 long time; one of them, advocated by Hansen (1893, 1925, 1930) 

 and accepted by other writers including Vandel (1949), maintains 

 that the insect coxa does not correspond morphologically to the cox- 

 opodite of the Crustacea but to the basipodite. Thus Hansen could 

 homologize the coxal stylus of the Machilidae with an exopod. And 

 on our part, we were tempted to see in the precoxopodite and coxopo- 

 dite of the Crustacea the probable equivalents of the main supracoxal 

 arcs of the Apterygota.^ 



However, the Crustacea Malacostraca compelled us to reject such 

 homologizing. As we were trying to find to what part of the leg base 

 the pleural region of the Apterygota corresponds, we had to acknowl- 

 edge the accuracy of a former opinion, which regarded the coxa simply 

 as homologous with the coxopodite; the correctness of this opinion 

 will so be proved. 



BASIPODITE AND COXOPODITE 



Our researches on the Malacostraca concerned various species, par- 

 ticularly Anaspides * and Penaeiis. We first studied Anaspides, which 

 is the "most primitive" genus of the subclass. The thoracic limbs of 

 this malacostracan, mainly the maxilliped, have been considered by 

 Hansen and other morphologists as having best preserved the organi- 

 zation of the primitive biramous limb. Neither Hansen ^ nor Snod- 

 grass,^ who has lately taken up the study of these appendages, saw an 

 independent precoxopodite. According to those authors the precox- 

 opodite of these "primitive" legs would be imbedded in the lateral 



3 Lameere (1935, p. 70) regarded these homologies as "probable." 



* Anaspides tasmaniae Thorns., specimens of which were sent to us by Prof. 

 E. Percival (Christchurch, New Zealand), thanks to the kind offices of our 

 colleague Prof. H. Damas (Liege). 



5 Hansen, 1925, pp. 102-103 and pi. 5, fig. 3e, f, h. 



« Snodgrass, 1952, p. 135, fig. C. 



