SEA-SPIDERg 



431 



IncertcE Sedis 

 Class Pycnogonida, Pantopoda, or Podosomata 



Marine Arthropods, sometimes called sea-spiders. They may be 

 ranked between Crustaceans and Arachnoids. Many climb about 



Fig. 244. — Under -surface of a Trilobite. — After Beecher. 



I, Antennae ; 2, mouth-appendages ; 3, the under-surface 

 of the head shield ; 4, the biramose thoracic hnibs; 

 5, the biramose abdominal limbs ; M., position of the 

 mouth. 



seaweeds and hydroids near the shore, but some live at great depths. 

 The body consists of an anterior proboscis, cephalothoracic region 



