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New Zealand Coelenterates Ctenophores from Cook Strait

Lesueuria pinnata sp. nov. Text Fig. IV

page 7

Lesueuria pinnata sp. nov. Text Fig. IV.

Specific Description: Four, papillated, fin-like flaps, are situated beside the meridional subventral bands of swimming plates and what appear to be short transverse canals are found below each swimming plate; oral lobes about one-quarter the total length of the animal and the auricles slightly shorter than the oral lobes; peripheral canal system at present unknown.

This species is common during calm weather in autumn but is very difficult to capture on account of its size and delicate nature, while an hour or so of confinement is sufficient to start disintegration. The description of this species is taken from the preserved specimen and observations on several living specimens. The average size of specimens was 160 to 200 mm. long and the largest was 290 mm. The stomodeum of the species is long and the infundibulum short. The meridional canals unfortunately are not distinct. In cross section the body is dumb-bell shaped, with the stomodeum corresponding in position to the handle of the dumb-bell. In general outline the body is long and considerably flattened in the tentacular axis, which has a deep wide groove running from the oral toward the aboral end and disappearing in the region of the funnel tube. There are two oral lobes of very delicate texture about one-quarter the total length of the body. The four auricles are straight and ribbon-like and somewhat shorter than the oral lobes. The stomodeal axis is 60 mm. in width and the distance between the meridional subventral and meridional subtentacular canals of opposite sides is 20 mm. Aborally, the end is bluntly pointed, and the subtentacular comb rows commence from the inner sides of two gelatinous projections that form a groove in which the sense organ is situated. Otherwise the rows of swimming plates are of the general lobate type with the individual plates very wide and short. What appear to be short transverse canals pass through the base of each comb plate. Gelatinous dark-coloured, fin-like flaps are situated beside the meridional subventral bands of swimming plates. Along the outer margin of these fin-like flaps is a row of tiny papillae each with a projecting centre. In the preserved specimens these could be traced to the margin of the oral lobe but this is difficult in the living specimens as the papillae are unpigmented in this region. Aborally, they are pigmented and show as a thin dark line. The centres of the papillae however are devoid of pigment. The rest of the animal is unpigmented and slightly opaque.