CEPHALOPODA OE THE HAWAIIAN ISLANDS. 
281 
Subfamily TREMOCTOPODIN.E. 
Pkilmexidce H. and A. Adams 1858, vol. i, p. 21. 
Tremoclopidce Tryou 1879, p. 130. 
Tremoctopodidm P. Fischer 1882, p. 334. 
Tremoctopodinae Berry 1912b, p. 386. 
Adult small. Third left arm of the male hectocotylized ; its outer surface ornamented with fringe- 
like papillae. Dorsal arms of female connected at base by a broad veliform membrane, which extends 
along their margins, leaving only the very attenuate and frequently decollated extremities free. Re- 
maining arms webbed only at the base, their suckers larger and better developed than those of the dorsal 
pair. No calcareous egg case or shell. Two large aquiferous pores on the dorsal aspect of the head and 
a smaller one at either side ventrally just in front of the funnel. Mantle articulating with the funnel 
by membranous folds; no definite locking cartilages. Fiuinel organ poorly developed and represented 
only by a series of longitudinal lamellae. 
Genus TREMOCTOPDS Delle Chiaje 1829 . 
Tremoctopus Delle Chiaje 1829, T. 70, 71 {fide Wiilker). 
Octopus {Pkilonexis) d’Orbigny 1835, p. 14. 
Philonexis d’Orhigny 1845, p. 200. 
Tremocioptis Naei 1912b. p, 199. 
Since only the single genus of the group is known, its characters are entirely those of the subfamily. 
Type. — Tremoctopus violaceiis Delle Chiaje 1829 (monotypic), a species originally described from 
the Mediterranean. 
Tremoctopus violaceus Delle Chiaje 1829. (PI. xlix, fig. 3, 4.) 
? Tremoctopus violaceus Delle Chiaje 1829, T. 70, 7x {fide Wiilker). 
Octopus gracilis Souleyet in Eydoux and Souleyet 1852, p. 13, pi. i, figs. 8-9. 
? Octopus dubius Souleyet in Eydoux and Souleyet 1852. p. 15, pi. r, figs, ia-14. 
? Tremoctopus dubius Tryon 1879, p. 131, pi. 43, fig. 80, 81 (after Souleyet). 
Tremoctopus gracilis Tryon 1879, p. 131, pi. 43, fig. 82, 83 (after Souleyet). 
Tremoctopus quoya7ius Hoyle 1904, p. 12, fig. A. 
Tremoctopus sp. (near guoyanus d'Orbigny) Berry 1909, p. 418 (locality record only). 
Animal small, pelagic. The sexes are so conspicuously dimorphic that a separate description is 
necessary. 
Female: Mantle short; width about equal to length; pouch-shaped, widest anteriorly, and either 
simply rounded behind or rapidly narrowing to a rounded point; a sharp median longitudinal groove 
on the ventral surface indicates the position of the median septum of the mantle cavity. Mantle opening 
very wide and full, extending to a point just above the center of the eye on either side, but well behind 
it; mantle of scanty extent below, so that its margin barely meets the posterior edge of the funnel. 
Head large, flattened; extremely short and broad, the large prominent rounded eyes rendering it 
usually wider than the body. Eyes not at all pedunculated. Entire stu-face covered by a loose 
smooth delicate skin or cuticle of hyaline consistency and impigmented, which is perforated by four 
small oval openings — the so-called aquiferous pores — a pair on the dorsal aspect being situated one at 
the base of each dorsal arm just a little outside the axis of the latter, and another pair about half as large 
situated one at the base of each ventral arm at either side of the tip of the frmnel. Funnel large, 
compressed, very broad at the base, its outline almost that of an equilateral triangle; only the narrow 
apex free. Funnel organ composed of a number of longitudinal lamellse or folds, terminated near the 
apex by a small acutely pointed valve-like flap. (PI. xux, fig. 4.) The base of the funnel just over 
the retraetor muscles articulates with pocket-like grooves on the inner surface of the mantle by means 
of a thickened and recurved fold of the posterior margin. 
Arms (pi. Xbix, fig. 3) slender, graceful; decidedly luiequal, order of length i, 2, 4, 3; dorsal arms 
decidedly longest and when perfect terminating distally in a very long delicate thread-like process ; second 
arm pair a little shorter than the first, notably stouter, wider and less attenuate ; third arms decidedly 
