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recently by Naef (1912&, p. 199). Wiilker has likewise reported under the same name a species of the 
genus from Japan (1910, p. 5). Not having any material from other regions available for comparison, 
I have felt constrained to follow the precedent thus made for me, especially since I have not been able 
to seize upon any characters of sufficient definiteness to separate the Pacific species from the Atlantic. 
Nevertheless it should be remembered that our knowledge of the group is still woefully incomplete, 
and a careful account is needed of all the diverse stages which specimens from the various regions pass 
through during their life history, before absolute confidence can be felt in such wholesale relegation to 
the synonymy. 
Should it eventually appear that there are more species of Tremoctopus than recent writers are 
inclined to admit, I have no doubt whatever that the Hawaiian specimens are identical with the form 
described by Souleyet as Octopus gracilis. Tryon (1879, p. 131) gives the following brief paraphrase of 
his very inadequate description: “Body rounded, smooth; head small; eyes large, prominent; arms 
graceful, the upper very long, lower short, connected by a web. Phosphorescent and with metallic 
reflections when living. Length 24 mm. ” 
Certainly these few lines contain little which can serve either to prove or to disprove the identity 
of Souleyet ’s specimen with those obtained by the Albatross, but upon turning to the fig;ure we 
find a representation which accords very well with Hawaiian specimens of the same size, and as both 
are from the same general oceanic region and the habit of the animals is admittedly pelagic, we find at 
once a strong a priori reason for uniting them. From the present specimens the fig;ure of O. gracilis 
differs most strikingly in its more inflated body (a character of trifling importance) and somewhat wider 
web between the ventral arms. The eyes are also represented as being semipedunculate, but I suspect 
that this appearance may be due to the loss of the delicate integument which usually envelops the head. 
The proportions of the arms are, however, much the same, and it is further noteworthy that a specimen 
presumably of this species taken by the Challenger in the western Pacific differs in no described char- 
acter from the Albatross specimens (Hoyle 1886, p. 71). 
With the same form I would be also disposed to unite the Octopus dubius, also of Souleyet, 
especially since the most immature of the specimens before me is almost a comiterpart of his figure 
and is of similar dimensions (6 mm.). 
The two female specimens dredged by the A Ibatross in the tropical Pacific , which Hoyle (1904, p. 12) 
referred with some doubt to T. quoyanus, likewise agree perfectly in all the characters stated, have the 
same curious arrangement of the chromatophores, and are surely conspecific. The single poorly pre- 
served individual taken by the Challenger in the south Pacific (Hoyle 1886, p. 70) also is probably 
identical, so that on the whole it can be affirmed with certainty that few Hawaiian cephalop)ods exhibit 
a wider distribution. 
The species is one of the most beautiful and graceful of all cephalopods. 
Family ALLOPOSID^ Verrill 1881. 
AllopostdceW tTXiW 1881, p. 365. 
Argonautidce (pars) Naet 1912b, p. 197, 198. 
Sexes dimorphic, the female larger than the male and often attaining considerable dimensions. 
Body soft and gelatinous, aquiferous pores lacking. Arms united throughout the greater portion of 
their length by an extensive umbrella; suckers in 1-2 rows. Hectocotylization affects the whole of 
the right third arm, which has its origin in a specialized sac in front of the eye, and when mature is most 
probably caducous. 
Genus ALLOPOSUS Verrill 1880 . 
Haliphron Steenstrup i8s9, p. 183 (nomen nudum, fide Hoyle). 
Alloposus Verrill 1880, p. 393. 
Alloposus Verrill 1881, p. 365. 
Alloposus Hoyle 1886, p. 72. 
Alloposus Naef 1912b, p. 198. 
This being the only known genus, its characters are entirely those of the family. 
Type. — Alloposus mollis Verrill 1880 (monotypic), originally described from off the New England 
coast. 
