78 THE VOYAGE OF H.M.S. CHALLENGER. 



There can be no doubt that this specimen is to be referred to the same species 

 as that figured by d'Orbigny {ia6. cit.), but there is much more difficulty in deciding by 

 what name it should be called. When the plates accompanying the " Cuba Memoir " 

 were drawn it is evident that d'Orbigny regarded it as varietally distinct from Octopus 

 vulgaris, Lmk., for the plate is lettered " Octojjus vulgaris, var. atnericanus," and 

 since this figure is really the type of the species, it would have been desirable to 

 elevate d'Orbigny 's designation into a specific name, and to quote him as the authority 

 for it. The first objection to this is that d'Orbigny seems to have abandoned his idea 

 of establishing this as a formal variety, for in his text he makes no further allusion 

 to its characteristic peculiarities than " Nous avons cru remarquer que les individus 

 americains, tout' en presentant les proportions et tons les autres caractferes de ceux 

 de nos cotes, sont neanmoins plus tachetes de rouge en dedans de I'ombrelle " {loc. cit., 

 p. 415). The second objection is more serious, and consists in the fact that the name 

 americanus has been already applied to an Octojn's by de Blaiuville,-' following 

 de Montfort,^ who applied the name " Poulpe americain " to a figure published by 

 Barker.^ The drawing was so insufficient that the name has never come into use, 

 and it would be quite impossible to demonstrate its identity with the present form. 

 Under these circumstances I have not felt justified in adopting d'Orbigny's name, but 

 have thought it better to use Steenstrup's MS. designation. 



The individual examined presents some curious irregularities in the disposition of 

 the suckers. The left dorsal arm has the six proximal suckers disposed in the usual 

 manner (the first four being in one series), and after them a gap, large enough to have 

 contained two suckers, which have been, as it were, dislocated on to the umbrella just 

 at the dorsal margin of the arm. The right dorsal arm has a supernumerary sucker 

 just beyond the eleventh ; and the third arm on the right side has the nine proximal 

 suckers arranged normally, but beyond them are two transverse rows, each containing 

 three suckers. Such deviations from the usual rule suggest the question whether 

 Tritaxeopus cornutus, Owen,* may not be merely a case in which a similar malformation 

 is more completely carried out. 



Octopus tuherculatus, BlainviUe. 



1826. Octopus tuherculatus, Blv., Diet. d. Sci. ISTat., t. xliii. p. 187. 



1838. „ „ d'Orb., C^pli. acet., p. 38; Poulpes, pis. xxi., xxiii. 



1869. „ „ Targ., CepL Mus, Eirenze, p. 18. 



Habitat. —Station 122b, ofi" Barra Grande, September 10, 1873; lat. 9° 9' S., 

 long. 34° 53' W. ; 32 fathoms ; red mud. One young specimen. 



iDiot. d. Sci. Nat., p. 189, 1826. ^ BuffondeSoimiiii,MoU.,t.iii. p. 30,pl.xsix., 1802. 



3 Phil. Trans., vol. 1. part 2, p. 777, pi. xxix. figs. 1-4, 1758. * Trans. Zool. Soc. Land., vol. xi. p. 131. 



