235 
of Edinburgh, Session 1880-81. 
body globular, slightly compressed laterally ; dorsal edge and posterior 
end convex, attached by extremity of ventral edge. Apertures 
both on wide anterior end, sessile, not conspicuous ; atrial, regularly 
lobed. Surface smooth. Colour white, with a hyaline tinge 
Length, 4 cm. ; breadth, 5 cm. 
Test cartilaginous, thickish, strong ; smooth and glistening on 
inner surface. 
Mantle not very thick ; muscle bands distinct, but distant. 
Branchial sac with seven folds on each side. Internal longitudinal 
bars strong, placed between as well as on the folds. Transverse 
vessels variable. Stigmata arranged in irregular transverse rows, 
rarely in spirals. 
Dorsal lamina short, but very wide ; plain. 
Tentacles large, branched, about twelve in number, placed larger 
and smaller alternately. One very large one occurs at the ventral 
edge, just anterior to the extremity of the endostyle. 
Olfactory tubercle a long way posterior to the tentacular circlet, 
equidistant from the branchial and atrial siphons; horns simply 
turned in, opening directed dorsally and to the left. 
One specimen from Station 150 (south of Kerguelen Island); 
150 fathoms. 
Molgula horridcc , n. sp. 
External appearance . — Shape rudely ovate; posterior end rounded, 
wide; anterior end narrower; ventral edge very convex, dorsal concavo- 
convex going from the anterior to the posterior end. Attached by 
the ventral part of the left side. Apertures both at the anterior 
end, not distant, slightly projecting, lobes irregular. Surface 
rough, almost entirely covered with sand, and other animals 
adhering. Colour — Where visible, the test is dull brown. Length, 
5 cm. ; breadth, 5 cm. 
Test thick and solid, very stiff; smooth and glistening on the 
inner surface. 
Mantle very thick, but not very muscular ; siphons wide, tubular. 
Branchial sac of a dark green colour, very thick ; seven folds on 
each side. Internal longitudinal bars prominent, connected by 
horizontal membranes ; transverse vessels irregular ; meshes square, 
and cut up by an irregular network, formed by vessels arising from 
