OCTOPODIDAE 485 



Family ARGON AUTIDAE 

 Genus Argonaut a Linne 1758 



Pelagic octopods in which the dorsal arms of the female are broadly- 

 expanded into glandular membranes that secrete and hold a delicate, cal- 

 careous shell for containing the eggs. The males are considerably smaller 

 than the females, do not have a shell, and the third right arm is modified into 

 a detachable copulatory organ which persists separately for a certain length 

 of time in the mantle cavity of the female. 



Argonaut a argo Linne Common Paper Nautilus 



Plates ic; 26y 



Worldwide in warm waters. 



4 to 8 inches in length, quite fragile, laterally compressed with a narrow 

 keel, numerous sharp nodules which in the early part of the shell are stained 

 with dark purplish brown. Rest of shell opaque, milky-white. Occasionally 

 washed ashore. A. americana Dall is the same. 



Argonaut a hians Solander Brown Paper Nautilus 



Figure gpe, f 



Worldwide in warm waters. 



Similar to A. argo, but smaller, much "fatter" with a rapidly broadening 

 keel that bears larger and fewer nodules. Color brownish white with darker 

 stains on the early part of the keel. Uncommonly washed ashore. 



Family TREMOCTOPODIDAE 

 Genus Tremoctopus Delle Chiaje 1829 



Tremoctopus violaceus Delle Chiaje Common Umbrella Octopus 



Pelagic in warm waters. Worldwide. 



Total length, including the arms, 3 to 6 feet. Deep purplish red in color. 

 Characterized by the long skin webs between the four dorsal arms, and the 

 two large holes in the body near the base of the third arm and in front of 

 the eyes. The species is gregarious, and is occasionally washed ashore on the 

 east coast of Florida. 



Family OCTOPODIDAE 



Genus Octopus Lamarck 1798 



There are only five valid species of littoral Octopus so far recorded 

 along the Atlantic Coast. There are a few deep water ones, some of which 



