Boone, Mollusca, Cruises of "Eagle" and "Ara," 1921-28 189 



The pen has a strongly denned midrib that tapers posteriorly and 

 widens decidedly anteriorly where it is bluntly truncated and slightly 

 rounded. Anteriorly the wings are represented by a slight, almost 

 linear margin, widening for about one-sixth of the pen 's length, thence 

 abruptly widening into a broad, convex-concave lamina with rounded, 

 thickened lateral margin ; posteriorly these wings narrow, converging 

 into a blunted rounded tip (see plate 117, fig. A). 



References : Sepioteuthis sloanii Leach, Mss. 1817 ; Gray, Catal. 

 Mollusks Brit. Mus., vol. I, p. 81, 1849.— Tryon, Man, Conch., vol. 

 I, Cephalopoda, p. 153, 1879. — Hoyle, Kept. Voy. "Challenger" 

 Zool., Cephalopoda, vol. 16, p. 27, 1886. — Boone, Bull. Bingham 

 Oceanog. Coll., vol. I, art. 3, p. 16, figs. 3, 4, 5, 1928. 



Suborder: Octopoda. 



Family: ARGONAUTIDAE. 



Genus : ARGONAUTA Linne. 

 Argonauta argo Linne. 



Plate 118. 



Type: Linne stated of his type: "Haoitat in Pelago, M. Indico, 

 M edit err aneo." 



Distribution: Mediterranean; tropic and subtropic Atlantic, 

 Cape of Good Hope, Madeira; east coast of the United States and 

 West Indies ; tropical American Pacific off Lower California, the Gulf 

 of California, the west coast of Mexico and Panama; Cocos Island. 

 Pelagic. 



Material examined: One egg-laden female with shell, from 50 

 miles off Cape Mala, Panama, March 16, 1926, caught by dredge on a 

 trip down 300 fms. 



Technical description : A very thorough diagnosis of this spe- 

 cies, based on material from the Mediterranean Sea, with most careful 

 figures, and including studies of the young stages, also a comprehen- 

 sive list of the literature from Aristotle to 1921 is given by Dr. Adolf 

 Naef in his "Die Cephalopoden, Fauna E Flora del Golfo di Napoli," 

 vol. 35, Bd. I, pp. 763, 788, text figs. 455-470, 1923. 



The "Ara" specimen is an egg-laden shell and female, the body 

 of which is 20 mm. long, the longest arm 40 mm. There are approxi- 



