367 
ri. E. Verrill — North American Gephalopods. 
Family OCTOPODID-iE D’Orbigny, (restricted). 
Octopodidce (pars) D’Orbigny, Moll. Yiv. et Fos., i, 159, 164, 1845 (t. Gray); (pars) 
Cephal. Acetab., p. 3. 
Odopidce (pars) Gray, Catal. Moll. Brit. Mus., i, p. 4, 1849. 
Body short, thick, rounded posteriorly, destitute of lateral fins and 
internal cartilages. Mantle united to the head by a broad dorsal 
commissure. Head very large. Connection between the mantle and 
base of siphon simple, without cartilages. Opening to the gill-cavity 
narrow. Median septum of branchial cavity short, extending for- 
ward to the base of the siphon, but running back only a short dis- 
tance. Siphon large, simple. Arms with either one or two rows of 
suckers, and with a more or less developed basal web. No cephalic 
aquiferous pores. Eyes furnished with an internal translucent lid, and 
also capable of being covered with the external integument. Sexes 
similar externally, except that the right arm of the third pair in the 
male is hectocotylized by the formation of a spoon-shaped organ 
at the tip. 
OCTOPUS Lamarck, 1799. 
Octopus (pars) Lamarck, Syst. des Anim. sans Vert., p. 60, 1801. 
Cuvier, Reg. Anim., ii, 1817. 
D’Orbigny, Cephal. Acetab., p. 3. 
Gray, Catal. Moll. Brit. Mus., i, p. 4, 1849. 
Body short, thick, more or less rounded, usually flattened, often 
tubercular or warty, but sometimes smooth, usually with one or more 
tubercles or cirri situated above the eye. Mantle directly united to 
the head, dorsally, by a broad commissure, extending below the eyes 
to the base of the siphon. Base of the siphon without any compli- 
cated connective cartilages. Arms united by a more or less extensive 
basal web. Suckers sessile, in two alternating rows. Siphon not inti- 
mately united to tlie whole length of the under side of the head, the 
free terminal portion situated behind or beneath the eyes. No aquif- 
erous pores, nor brachial pouches. 
The sexes are similar in form. In the male the right arm of the 
third pair is hectocotylized, its terminal portion being changed into 
a spoon-shaped organ, smooth on the outer convex side and furnished 
with a series of transverse ridges on the inner concave side, and with 
a basal angular lobe from which a groove or furrow extends along 
the lower margin of the arm to the basal web. In some species of 
Octopus this modified tip is very small, but in others very large. 
The female has oviducts on both sides. Eggs comparatively few 
