538 ON A STALK-EYED CRUSTACEAN 
its great basal scale being very largely developed. Behind these 
follow about seven slender, filiform, jointed limbs, diminishing in 
length from before backwards ; indistinct traces of a second division, 
or exopodite, are discernible in these limbs. 
Notwithstanding the imperfect condition of this new specimen, 
and the very little that it enables me to add to what was already 
known of Pygocephalus, it is so desirable to call the attention of 
collectors to the various aspects under which the higher Crustacea 
make their appearance in the oldest rocks at present known to con- 
tain them, that I venture to communicate the present notice to the 
Geological Society. 
