ORDER TRACHEARI.E. 499 



or like a trefoil. It carries at its base the forceps and the 

 palpi. The forceps are cylindrical or linear, simply prehensile, 

 composed of two pieces, the last of which is pincer-like, with 

 the lower claw, or that which is immoveable, sometimes 

 shorter. The palpi are in the form of a thread, of five, or 

 nine articulations, with a hook at the end. Each following 

 segment, with the exception of the last, serves as an attach- 

 ment to a pair of feet ; but the first, or that with which the 

 mouth is articulated, has on the back a tubercle, carrying on 

 each side two simple eyes, and underneath, in the females 

 only, two other small feet, folded back upon themselves, 

 and carrying the eggs which are assembled all around them, in 

 one or two pellets. The last segment i.s small, cylindrical, 

 and pierced with a little hole at its extremity. No vestiges 

 of stigmata arc discoverable. 



These animals are found among marine jdants, sometimes 

 under stones, near banks or shores, and sometimes also on 

 cetaceous animals. 



PycnogonUxM, Bran., Midi., Fah., 



Are without forceps or palpi, and the length of their feet but 

 little exceeds that of the body, which is proportionably shorter 

 and thicker than in the following genera. They live on the 

 cetacea. 



Pjioxichilus, fnlr., 



Present no palpi, as in the preceding, but have very long feet, 

 and two antennae-pincers. 



NyMpiroN, Fah., 



Resemble the Plioxichili, in the very narrow and oblong form 

 of their body, the length of their feet, and the presence of 

 antennae-pincers, or forceps ; but they have, besides, two 

 ])alpi. 



K k 2 



