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Proceedings of the Royal Society 
ally plicated. Transverse vessels all narrow. Papillae only at the 
angles of the meshes, long, tapering, and curved like tusks. Broad 
membranes hang from the transverse vessels, and are stretched over 
the convex sides of the papillae and attached to their apices. Three 
to five stigmata in a mesh. 
Dorsal lamina very broad in its lower half, transversely ribbed, 
and minutely tuberculated at the edge. 
Tentacles 35 to 40, long, crowded, their bases touching, of different 
lengths but not alternating. 
Olfactory tubercle oval in outline. 
Several specimens from Station 49 (South of Nova Scotia), 83 
fathoms. 
A few of the specimens are not so much depressed as the others, 
and have rather an oblong shape and terminal apertures. 
This species shows considerable resemblance externally to Ascidia 
obliqua , but differs from it in the structure of the branchial sac, 
and especially in the form and arrangement of the papillae. 
Abyssascidia, n. gen. 
Test cartilaginous, transparent. Branchial aperture about 12 
lobed, atrial about 8 lobed. Attached by ventral surface. 
Mantle thin. A few large distant muscle bands on the left side. 
Branchial sac not longitudinally plicated. 
Tentacles simple, filiform. 
Viscera on the right side of the branchial sac, intestine small, 
stomach short and wide. 
Reproductive organs forming a round mass situated on the right 
side of the intestinal loop. 
Abyssascidia wyvillii , n. sp. 
External appearance. — Shape oblong, rather pointed at the anterior 
end, rounded at the posterior end ; attached to a small manganese 
nodule by the lower (ventral) surface in front of the middle ; flattened 
so that, the branchial aperture being anterior, the atrial is on the 
upper surface three-quarters of the way to the posterior end, and 
rather to the right of the middle ; in consequence of this, more of 
the left than of the right side enters into the formation of the upper 
