300 



BULLETIN OF THE BUREAU OF FISHERIES. 

 Specimens of Polypus a Examined. 



Remarks. — The long, graceful arms give this curiously shaped little Polypus a most characteristic 

 spidery appearance. As already indicated, the specimens bear all the evidences of immaturity, and I 

 think there is good evidence that they are but the young of P. ornatus, the adult of which they resemble 

 in their arm formula and short umbrella. However, as this is not quite certain and they have so unique 

 a facies of their own, it has seemed best to give them provisional consideration by themselves. In 

 recalling the discussion I have given on a preceding page regarding the relationships of P. ornatus, it is 

 interesting to note that these young individuals are exceedingly suggestive of the young of P. macropus 

 (Risso) as figured by Jatta in his Naples monograph ( i8q6, pi. 24, fig. 2). Should my belief that 

 these are juvenile ornatus be correct, another striking bit of evidence of the close affinity of that species 

 with P. macropus is afforded. 



Polypus /3 (young). (PI. xuvin, fig. 7, 8.) 

 Polypus (1 Berry 1909. p. 41S (merely listed). 



Body compact, slightly longer than broad, little tapering, squarely rounded posteriorly; flattened 

 above, more inflated below, with a distinct longitudinal sulcus in the middle, and sometimes a curved 

 constriction or groove nearly paralleling the mantle margin and just behind it. Surface almost smooth, 

 but the dorsum very faintly and regularly papillose, especially between the eyes; just above and a 

 little posterior to each eye opening is a small blunt tubercle, with one or two fainter ones sometimes 

 to be distinguished near it. Mantle opening wide, reaching nearly to the eyes. 



Head short, broad, compressed, flattened above. Eyes moderately large and prominent. Funnel 

 short, bluntly conical; barely reaching to the base of the arms; broadly adherent above to the head for 

 a large part of its length. 



Arms robust, little attenuate; very short, but about half again as long as the head and body; nearly 

 equal, the dorsal pair as a rule slightly the shortest. Umbrella well developed, but only about half as 

 long dorsally as ventrally and attaining its maximum between the arms of the third and fourth pairs, 

 along which it reaches for about one-third of their length; marginal membranes present on the arms as 

 continuations of the umbrella, but much reduced and almost keel-like. Suckers numerous, large, 

 slightly elevated; closely placed, the first two to four in a single row, the remainder alternating and 

 biserial. 



Ground color everywhere a brownish buff, rather pale', but closely dotted above with numerous 

 minute slate-colored chromatophores. A double row of very large, irregular, chevron-shaped chroma- 

 tophores extends from the base along the outer surface of all the arms, but early becomes obscure on the 

 two ventral pairs. In very young individuals (of a length of 12 mm. or less) the ventral surface of the 

 mantle is ornamented by a number of large irregularly ovoid chromatophores arranged in transverse 

 rows, and there is a single very distinct dark-colored series bordering the nuchal constriction. Such 

 specimens are apt to be a little more globose than those further advanced. 



