of Edinburgh, Session 1879 - 80 . 463 
Mantle thick on the right (branchial) side of the body, and on the 
tubes, but not very muscular ; membranous on the large distended 
left (visceral) side. Tubes long and rather narrow. 
Branchial sac long and narrow, pointed at the posterior end ; 
plicated longitudinally, the internal longitudinal bars being placed 
on the ridges. Meshes transversely oblong, each containing about 
six stigmata. Papillae all of one size, irregular in shape, often cleft 
or lobed. 
Dorsal lamina ribbed transversely, and bearing small teeth on its 
free margin. 
Tentacles filiform, slender, alternately large and small ; probably 
30 to 35 in number. 
Two specimens from Station 162 (Bass’ Straits), 38 to 40 fathoms. 
In both specimens almost the whole of the test is gone, which 
makes it impossible to give the external characters with certainty. 
The branchial aperture also is damaged in both to such an extent 
that the exact number of tentacles and the nature of the olfactory 
tubercle cannot be determined. This species is closely allied to the 
last. 
Pachychlcena gigantea , n. sp. 
External appearance . — Shape, as far as can be made out, irregu- 
larly oblong, the right side being larger than the left. Probably 
attached by the posterior part of the ventral edge. Branchial 
aperture terminal, on a large irregularly rounded projection turned 
towards the left side. Atrial aperture on the dorsal edge, also on a 
large projection, situated more than one-third of the way down. 
Lobes of apertures irregular but prominent. Surface very irregular 
and almost covered by Polyzoa , Hydroida, Algae , &c. Colour of a 
warm yellowish-grey where the test itself is seen. Length about 12 
cm.; breadth, 5 to 7 cm. 
Test cartilaginous, very thick (2 mm. to 4 cm.) and solid, white in 
mass with a hyaline tint where thin, yellowish-grey on the external 
surface. Large vessels ramify in the inner layer ; the vascular trunks 
probably enter the test at the base of the right side towards the 
ventral edge. 
Mantle strongly muscular over the right side and on the tubes, 
