56 Proceedings of the Royal Society 
sloping backwards to the broad and rounded posterior end. 
Attached by the posterior two-fifths of the ventral edge. Branchial 
aperture terminal, on a large projection turned ventrally and to the 
left side ; atrial aperture also prominent, on the dorsal edge, three- 
fourths of the way down, and directed dorsally. Surface wrinkled 
and minutely grooved, but not covered with excrescences ; some- 
what corrugated round the apertures, a few foreign bodies adhering. 
Colour pale yellow, with a reddish-brown tinge here and there. 
Length, 7 ‘5 cm. ; breadth, 5 cm. 
Test leathery, tough, rather thin. Inner surface white and 
glistening. 
Mantle strongly muscular on the right side ; membranous over 
the viscera. A narrow membrane projects into the branchial siphon 
above the tentacular circlet ; it is slightly crenated, but does not 
bear large conical processes as in M. lielleri. 
Branchial sac with seven folds on each side. Internal longi- 
tudinal bars numerous ; about six on the folds, and the same num- 
ber on the interspaces. Meshes transversely elongated, containing 
each about twelve stigmata; generally a fine transverse vessel 
divides the mesh horizontally. 
Dorsal lamina not broad, but rather thick ; edge plain. 
Endostyle very broad. 
Tentacles about twenty in number — six large, six small, and 
some intermediate very minute ones not present in all the inter- 
spaces. 
Olfactory tubercle irregularly cordate ; both ends turned in. 
One specimen from Station 162 (Bass’ Strait), 38 to 40 fathoms. 
This species is nearly allied to M. lielleri, from which it differs 
chiefly in having fourteen folds in its branchial sac instead of 
twelve, and in the condition of the diaphragm in the branchial 
siphon. 
Cynthia , Savigny. 
This genus is used here in the most restricted sense, as proposed 
by Heller : * — 
* Untersuch. u. d. Tun. Adriat. u. Mittelm., iii. Abth. p 9. 
