THE PYCNOGONIDA. 



333 



On the other hand, the hexapod larva of the Fycnogonida 

 differs from the hexapod Nauplius of the Crustacea, inasmuch 

 as the three pairs of appendages of a Mtupllus always repre- 



PiG. %2.—MacroUotus SchiiUzei {x. 100),— «, month with six oral papillae ; 6, cnllet, 

 calcified etylets; c, salivary <,'laiids ; d, muscular pharynx ; e, ovary;/, vesicula 

 Bemiaalis ; g, testis; 1, 2, 3, 4, limbs. (After Greeff.i) 



sent antennary and mandibular appendages, and these, by the 

 hypothesis, are to be sought in the rostrum of the Fycnogo- 

 nida. 



The fact to which reference has already been made, that 

 the embryo Scorpion has six pairs of rudimentary appendages, 

 attached to as many of the anterior free somites, of which one 

 pair only remain (as the pectines) in the adult, leads me to 

 suspect that the Pycnogonida may represent a much modified 



1 " Untersuchungen iiber den Bau der Barthlerclien." (" Arcliiv fiir mikr. 

 Anat.," 1866.) 



