CEPHALOPODA 



613 



Family 2. OCTOPODIDAE. 



Devil-fishes. Head very large; arms elongatetl, webbed, similar; 

 suckers in 2 rows and sessile; mantle united to the head by a broad, 

 dorsal commissure; third arm on right hectoeotylized : about 8 genera. 



Octopus Lamarck. Sea polyp. Body round; arms long; no fins: 

 50 species; cosmopolitan; 2 species on the Pacific coast, 4 on the Atlantic. 



0. bairdi Yerrill (Fig. 963). Body 

 short, thick, covered with small tubercles, 

 75 mm. long, 35 mm. wide, bluish-white in 

 color, specked with brown; arms short, 10 

 cm. long, webbed a third of their length: 

 common north of Cape Cod in rather deep 

 water; Europe. 



0. punctatus Gabb. Body ovate, 9 mm. long; length of arms 22 

 mm.; color red, spotted: common from Alaska to Lower California, in 

 tide pools; it grows much larger in open water, where the length of the 

 body may oe 30 cm., and that of the arms 5 m. 



Fig. 963 — Octopus halrdi 

 (Verrill). 



