Family Cranchiidae
Genus Megalocranchia Pfeffer, 1884
1884. Abhandl. Naturwissen Vereins Hamburg, vol. 8, p. 24.
Type Species (monotypy) : Megalocranchia maxima Pfeffer.

Megalocranchia richardsoni, n.sp. Figs. 7-10.

Animal large for the group, body narrowly conical, but constricted anteriorly. Mantle thin, smooth, membranous, constricted considerably just behind the anterior margin, then rapidly swelling to attain its maximum diameter, tapering at first gradually and then suddenly to a fine attenuate point at the posterior extremity. Fins large, elongate, thin and fragile, somewhat damaged at the posterior extremity in all specimens but apparently continuous about the posterior extremity of the body, extending from one-half to one-third the mantle length, inserted along their whole length into dorsal mantle wall, towards the posterior half of their attachment closely appressed to the lanceola of the pen. Anterior margin of mantle attached to the head and funnel in three areas. The mantle is attached to the head by a comparatively narrow band in the mid-dorsal line and to the funnel towards each lateral wing. A faint darkened line indicates the mid-dorsal line over most of the mantle, bifurcating posteriorly to outline the lanceola and joining a similar faint, dark line which indicates the line of attachment of fin and mantle on each side.

Head short and narrow without the eyes. Width of head including eyes considerably greater than the mantle width. Eyes very large and prominent, non-pedunculate but attached to the sides of head, almost circular in lateral view and projecting obliquely downwards. A large semi-circular photogenic organ occupies the ventral surface of the eyeball.

Funnel comparatively large, thin walled, broad at base, almost completely filling the area of head between the eyes. Funnel organ (Fig. 10) well-developed, consisting of a large median dorsal organ with a smaller sub-triangular pad-like lateral organ on each side. Dorsal organ rather crescent-shaped with three rather pointed projections, one from each lateral wing and one from the posterior median margin.

Arms well-developed, short, the longest approximately two-fifths the mantle length, distinctly unequal, order of length more usually 3, 2, 4, 1, but occasionally 3, 4, 2, 1, the second and fourth pairs subequal. No umbrella. Sessile arms bordered by a delicate, narrow, lateral membrane on each side. Arms with a double row of stalked suckers, the largest on the second and third pairs situated about the distal fourth. Sucker rings smooth.

Tentacles moderately stout, comparatively long, between a half and four-fifths the mantle length, expanded at tips to form clubs which are bounded by a thin lateral membrane on each side. A small median membrane extends along the distal third of the outer face of each club. Club set with rows of long stalked suckers, four suckers of comparable size in each row, the largest suckers in the middle of the club, diminishing in diameter distally and proximally, about 11 rows on body of club and about 12 rows of very small suckers on the distal extremity of club. Stalk of tentacles set on inner faces with pairs of close-spaced suckers, the pairs arranged in a zigzag fashion. Suckers of main portion of club set with horny rings (Fig. 9) which bear some eleven narrowly pointed teeth on the superior circumferance, teeth reduced to small rounded bosses on inferior margin.

Living animal almost transparent except for brownish-black chromatophores. Preserved specimens a dirty white with reddish-brown chromatophores. Chromatophores page 11

Figs. 7,8.—Megalocranchia richardsoni n.sp., Holotype. 9.—Megalocranchia richardsoni n.sp., ring from sucker on tentacle club. 10.—Megalocranchia richardsoni n.sp., funnel organ 11.—Enoploteuthis neozelanica n.sp., diagrammatic view to show disposition of photophores. 12.—Enoploteuthis neozelanica n.sp., Holotype. 13—Enoploteuthis neozelanica. n.sp., left tentacle club.

page 12 small and close on integument of anterior portion of head and outer surface of arms, large and irregularly shaped on dorsal and ventral surfaces of head and rather oval-shaped and large on mantle. Little discernible pattern in arrangement of chromatophores on mantle but a general bilateral symmetry. A narrow line of small chromatophores down the mid-dorsal line, overlying the gladius.

Holotype (M.12940) and three paratypes in Dominion Museum, Wellington.

Localities: B.S. 204, 37° 29′ S, 177° 17′ E, White Island Trench, c. 250 fathoms over c. 600 fathoms, m.v. Alert, 25.2.57 (Holotype); VUZ 57, 42° 1′30″ S, 174° 50′ E, south of Cape Palliser in c. 300 fathoms over 1,200–1,300 fathoms (para-type) ; VUZ 85, 41° 47′ S, 175° 2′ E, south of Cape Palliser in c. 600 fathoms over c. 800 fathoms (paratype); VUZ 110, Cook Strait, "Middle ground", fish stomachs from about 70 fathoms, coll. R. Greco (paratype).

This species seems a typical Megalocranchia related to M. maxima Pfeffer but distinguished from it by the relatively enormous development of the eyes. This feature, in fact, separates it from all other described species of the genus. This is the second species of Megalocranchia to be recorded from Cook Strait. The writer has already reported and figured M. pardus Berry (Dell, 1952, p. 135). Although the specimen of M. pardus from Cook Strait is smaller than the new species it is not much smaller than the smallest specimen of richardsoni and there is no possibility that it represents a juvenile stage. From pardus it differs in the different mantle shape, wider body and immense eyes. From M. abyssicola (Goodrich) it differs in the size of the eyes and the shape of the mantle. The eyes are easily damaged and the specimens collected have often had one or both missing or torn off in the trawl.