A. E. Verrill — North American Cephalopoda. 
302 
Gill-opening very wide, extending upward beyond the eyes. Arms 
long, slender; web rudimentary. Suckers prominent, iu two alter- 
nating rows. Siphon large, intimately united to the whole length of 
the lower side of the head; its free extremity is situated far forward, 
bet ween tHe ventral arms. 
The sexes are widely different. The hectocotylized arm of the 
male is developed in a pedunculated sac. 
There is a large aquiferous pore just behind the base of each ven- 
tral arm, at the sides of the siphon ; these connect with large, cephalic, 
aquiferous cavities. The connective cartilages on each side of the 
base of the siphon consist of a prominent button, with an expanded 
and recurved anterior edge, which fits into a corresponding deep pit 
in the mantle-cartilage ; and a deep, triangular pit, in front of the 
button, which receives the pointed, angular, cartilaginous tubercle 
of the mantle-cartilage. The posterior border of the base of the 
siphon forms a broad collar, within the mantle border. The lateral 
openings to the gill-cavity, on the sides of the neck, extend up as far 
as the upper side of the eyes ; opposite and below the eyes, they are 
large, but internally are interrupted by two muscular bands on each 
side, one running back from the head to the mantle and one going 
back from the base of the siphon, opposite the connective cartilage. 
The median septum of the gill-cavity is strong, but short, com- 
mencing a little behind the base of the siphon and extending only a 
short distance back, but expanding in length as it joins the ventral 
surface of the mantle ; behind it the two halves of the gill-cavity are 
connected by a wide opening. The peritoneal membrane is strong, 
and specked with dark chromatophores. 
Parasira catennlata Steenstrup. 
Octopus tuberculatus Risso (?), Hist. nat. de 1’Eur. merid., iv. p. 3, 1826 (t. d’Orb.) 
Octopus catenulatus Ferussac, Poulpes, pi. 6, bis, ter., 1828 (t. D’Orbig.) 
Philonexis tuberculatus Fer. and D’Orb., Ceph. Acet., p. 87, pi. 6, bis, ter. 
Parasira catenulata Steenstrup. 
Verrill, Amer. Journ. Sci., xix, p. 293, Apr., 1880. 
Plate XXXIII, figures 2, 2a. 
Female: Body relatively large, swollen, rather higher than broad, 
dilated below, larger in front, obtusely rounded posteriorly ; upper 
surface smooth or finely wrinkled ; lower surface covered with promi- 
nent, rounded verrucae or small hard tubercles, which are connected 
together by raised ridges, five (sometimes six) of which usually run 
to each tubercle, thus circumscribing angular depressed areas, each 
