EXPLORATION OF ALASKA. 203 
The length was 32.0 mm., by a breadth of 19.0 mm., and a height of 
13.0 mm.; the breadth of the foot 12.5 mm., of the mantle-brim 3.0 
mm.; the height of the rhinophoria 3.0 mm., of the branchial leaves 
2.5 mm.; the length of the genital opening 2.25 mm. 
The form was elongate-oval, somewhat larger than that of the Zam. 
bilameliata. The papille of the back relatively smaller and more 
rounded than in that animal. ‘The openings of the rhinophor-holes 
an oblique oval slit; the margins plain; several (six to eight) larger® 
papilla (of about 1.0 mm. in height) in the immediate vicinity of the 
holes; the club of the rhinophoria with about thirty leaves. The 
branchia with about ten leaves. The anal papilla low, with a stellate 
aperture ; the renal orifice as usual; the interbranchial space crowded 
with rather pointed and high papille. The head and tentacles as in 
allied forms. The genital papilla of oval form, with a large, longitu- 
dinal, crescentic slit. The rather broad foot with the usual anterior 
marginal furrow. The peritoneum colorless, without spicula. 
The central nervous system more flattened than in allied forms; 
the cerebro-visceral ganglia reniform, a little broader in the anterior 
part; the pedal ganglia less flattened than the former, larger than the 
visceral ones, of oval form, on the outside of the cerebro-visceral. The 
proximal olfactory ganglia a little smaller than the buccal ones, bulbi- 
form; distal ganglia could not be found. The commissure not broad, 
not short. The buccal ganglia of oval form, closely connected ; the: 
gastro-cesophageal roundish, rather long-stalked, in size about one-- 
sixth of the former, with one large cell and several (three or four) 
smaller ones. 
The nervi optici rather long; the eyes with yellowish lens and 
black pigment. The otocysts in the usual place, filled with otokonia 
of the usual kind. The leaves of the club of the rhinophoria very 
richly furnished with thick (diameter, 0.04 mm.) and long spicula, 
more or less calcareous, and very often giving off a thick twig of 
greater or less length (Pl. V, fig. 12); for the most part set perpen- 
dicularly or obliquely on the free margin of the leaves. The axes of 
the organs and the short stalk stuffed with strong and very much cal- 
cified spicules. In the skin of the back a mass of spicula of the same 
kind (Pl. IV, fig. 13) as above, or still more hardened ; the papille of 
the back solidified in the usual way (Pl. V, fig. 11). In the interstitial 
tissue fewer and smaller spicules. 
The oral tube rather short, wide. The bulbus pharyngeus of usual 
form, about 5.5 mm. long by a height of 4.5 mm., (and at the upper 
2, 
