PANTOPODA OR PYCNOGONIDA. 
379 
seaweeds and hydroids near the shore, but some live at great depths. 
The body consists of an anterior proboscis, cephalothoracic region 
with three fused and three free segments, and an unsegmented rudi- 
mentary abdomen. Four some- 
what primitive eyes on an anterior 
hillock, are nearer to the eyes of 
Arachnoids than to those of any 
other class. There are typically 
seven pairs of appendages. The 
first are short and chelate, but 
may be absent in the adult. 
The next two are small and 
slender, and are often absent in 
the adult female ; the second pair 
may also be absent in the male, 
but the third in the males of all 
genera carries the eggs. The 
last four pairs of appendages are 
always present, and form the 
walking legs. Into them, and 
Fic. 203.—Sea-spider (Pycnogonum 
littorale), from the dorsal surface. 
into the chelicerze when these are present, out-growths of the mid-gut 
extend. The sexes are separate» The larvee are at first unsegmented, 
with three pairs of appendages, 
Fic. 204.—Male of Nymphon.—After Sars. 
PR., Proboscis; CH., chelophores; P., pedipalps; Z., eggs carried on 
ovigerous legs; A., rudimentary abdomen. 
Examples.—Lycnogonum, Nymphon, A mmothea. In Pentanymphon 
and Decolopoda there is.an extra pair of long walking legs. 
