237 
of Edinburgh, Session 1880-81. 
The widest part is one-third of the way down, and from there both 
dorsal and ventral edges taper rapidly to the posterior end; not 
attached. Apertures at the extremities of the flat anterior end, not 
projecting, inconspicuous ; branchial rather the more anterior of the 
two. Surface entirely covered with a close coating of sand grains. 
Colour dark brown. Length, 2 cm. ; breadth, 1 ‘5 cm. 
Test thin, but stiff. 
Mantle thin. Musculature moderately developed. 
Branchial sac , with seven folds on the right side and six on the 
left. These folds have no stigmata, but consist merely of an open 
network formed by internal longitudinal bars and transverse vessels, 
which are frequently joined across the intervening stigmatic region 
by horizonal membranes. Fine interstigmatic vessels, arranged in 
rather distant and irregular rows of spirals. Stigmata curved in 
the spirals, and more or less linear between. 
Dorsal lamina narrow and plain. 
Tentacles branched, of many sizes. 
Olfactory tubercle tubular, having a wide funnel-shaped aperture 
anteriorly ; no horns. 
One specimen from Station 320 (off the coast of Buenos Ayres), 
600 fathoms. 
Eugyra herguelenensls , n. sp. 
External appearance . — Shape globular ; very slightly elongated 
dorso-ventrally ; not compressed laterally ; posterior end rounded, 
not attached. Apertures both anterior, conspicuous, not distant ; 
branchial sessile ; atrial prominent, forming a short cylindrical pro- 
jection. Surface smooth; slightly wrinkled round the apertures. 
Colour light transparent grey. Length, including atrial siphon, 
2 cm. ; breadth, 1 *8 cm. 
Test very thin and transparent, except on the atrial siphon. 
Mantle thin. Muscular fibres few, radiating from the apertures. 
Branchial sac strong; not folded. Internal longitudinal bars 
broad and thin bands. Transverse vessels slight and irregular ; 
narrow horizontal membranes usually present. Spirals large and 
much coiled, having from ten to thirty turns (generally fifteen to 
twenty). Radiating vessels slight ; a few short intermediate ones 
frequently present. 
