THE PYCNOGONIDA. 



333 



On the other hand, the hexapod larva of the Pycnogonida 

 differs from the hexapod Nauplius of the Crustacea^ inasmuch 

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



PiQ. ^I.—Macrobiotus Sehultzei (x 100), — a, mouth with six oral papillte ; 6, snllet, 

 calcified stylets; c, salivary glauds ; d, muscular pharynx ; «, ovary:/, vesicula 

 Bcmiualis ; flf, testis ; 1, 2, 3, 4, limbs. (After Greeff.^) 



sent antennary and mandibular appendages, and these, by the 

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

 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 " Untersucliungen iiber den Bau der Bllrthierclien." (" Arcliiv far mikr. 

 Anat.," 18G6,) 



