CEPHALOPODA OF THE HAWAIIAN ISLANDS. 



299 



[Polypus fontanianus (d'Orbigny 1835).] 



Octopus fontanianus d'Orbigny 1S35, p. 28, pi. 2, fig. 5. 



Octopus fontanianus Tryon 1879. P- 123. pi. 37. fig- 54 (after d'Orbigny). 

 This species is rather uncertainly listed from the "Sandwich Islands" by Tryon (I. c, p. 124) on 

 the authority of a specimen stated to be in the collection of the Academy of Natural Sciences of Phila- 

 delphia. It is a South American species and hence its occurrence in 

 Hawaii needs a confirmation which it is not likely ever to receive. 



As the collections before me are unusually rich in immature individ- 

 uals of this genus, some of which do not seem referable to any of the named 

 species, I have thought it worth while to present a brief description of 

 each of the various types into which as a rule the specimens may be easily 

 separated. 



Polypus a ( young) . 



Polypus a Berry 1909, p. 418 (merely listed). 



Two juvenile Polypi in the A Ibatross collection agree in the following 

 assemblage of characters: 



Body relatively large, ovate, saccular; much inflated, especially 

 below; broadest anteriorly and terminating in an obtuse point or nipple- 

 like projection behind. Mantle approximately smooth, with no definite 

 papillae, tubercles, or cirri; mantle opening wide, extending to just below 

 the eyes. 



Nuchal constriction prominent, almost furrow-like. Head short, 

 broad, flattened. Eyes inconspicuous, slightly protruding, with very 

 small apertures. Funnel large, but not reaching to the base of the arms; 

 in shape bluntly conical. 



Arms long, slender, attenuate; very unequal, the order of length i, 2, 

 3, 4; connected at the extreme base by a short , delicate umbrella of nearly 

 equal extent all around. Suckers small, numerous, crowded, in two rows. 



Color of preserved specimens everywhere pale, without markings of 

 any kind. 



With one of the two specimens mentioned are two much smaller 

 individuals (about 27 mm. long), which may represent an even younger 

 stage of the same species, but they differ from those described in their 

 shorter, more uniform arms, much larger eyes, and more oval body. 



Measurements of Polypus a. 





i- 



Fig. 16.— Polypus a [192], ventral 

 view of immature specimen 

 from station 3843, X 2. Drawn 

 by R. L. Hudson. 



Number in author's register 



Total length 



Tip of body to base of dorsal arms 



Length of body (dorsal) 



Width of body 



Width of neck 



Width of head 



Length of— 



Right dorsal arm 



Left dorsal arm 



Number in author's register. . 



Length of — 



Right second arm 



Left second arm 



Right third arm 



Left third arm 



Right ventral arm. . 



Left ventral arm 



Umbrella between dorsal arms. . 

 Umbrella between ventral arms 

 Funnel 



