palp 

 "proboscis 



^second tibia 

 tarsus 

 propodus 

 terminal claw 

 ■auxiliary claws 



first coxa 

 second coxa 



third coxa 

 femur 



Figuj-e 1. — Anatomy of a typical Pynogonid. 

 anterior view of whole animal. 



Inset: 



femoratum and Tanystylum orbiculare have been 

 less well studied, though P. femoratum is well 

 known to live on Tubularia, and its young pro- 

 duce parasitic galls on the hydroids. Pycnogon- 

 um littorale is reported to associate with sea 

 anemones (Prell, 1909). 



The remainder of the species in this key are 

 found primarily in deeper water, and, as ex- 

 pected, less is known of their habits. Species 

 heretofore collected only deeper than 100 m have 

 not been included, but some may yet appear in 

 collections from near the shelf edge. 



No new species have been reported from this 

 area since Joel W. Hedgpeth's (1948) compre- 



hensive systematic treatment. It was from this 

 work that much of the material in the key is 

 derived. I wish to thank Dr. Hedgpeth for his 

 kindness in permitting us to draw so heavily on 

 his paper and allowing us to reproduce many 

 of his drawings. 



Primary taxonomic characters for the pyc- 

 nogonids are combinations of presence or ab- 

 sence of chelae, palps, and ovigers. The number 

 of segments per appendage is also important. 

 Figure 1 portrays a generalized sketch of a 

 pycnogonid, illustrating characters used in the 

 key, and the inset depicts the lifelike appearance 

 of a whole animal. 



