466 THE INVERTEBRATA 



The Notostigmata mentioned above (p. 464) are forms transitional 

 between the acarines and the phalangids. 



Class PANTOPODA (PYCNOGONIDA) 



Arachnida, in which the opisthosoma has disappeared, with the 

 exception of the pregenital segment which bears legs on which the 

 genital pore opens. 



Fig. 345. A phalangid, Oligolophus spinosiis, adult (J, X 2. i, chelicerae; 

 2, pedipalps; 3, 4, 5, 6, walking legs. From Shipley and MacBride. 



These extraordinary animals, e.g. Nymphon (Fig. 346 A), are all 

 marine and semisedentary, crawling slowly over seaweed and seden- 

 tary animals. They consist of the following regions: (i) the proboscis ^ 

 a prolongation of the prosoma with the mouth at the tip ; (2) four 

 segments fused together bearing four eyes, the chelicerae, the pedi- 

 palps, the ovigerous legs which are present in both sexes and the first 

 pair of walking legs ; (3) three free segments bearing the remaining 

 pairs of walking legs. The body is usually very small while the legs 



