60 
Proceedings of the Royal Society 
Olfactory tubercle simple, rudely cordate in outline, opening 
anterior, both horns turned inwards. 
Several specimens from Station 186 (Torres Straits), 1 to 8 
fathoms. 
Oynthia irregularis , n. sp. 
External appearance. — Shape very irregular. Attached to a 
fragment of a shell by the right side near the dorsal edge and half- 
way up from the posterior end. Posterior end small, nearly flat ; 
anterior end broad, deeply cleft between the large divergent siphons, 
on the extremities of which the apertures are placed. Branchial 
aperture at the ventral edge of the anterior end, prominent, turned 
ventrally and a little to the left ; atrial aperture at the dorsal edge 
of the anterior end, not quite so prominent as the branchial, turned 
dorsally and a little to the left. Surface very uneven, deeply 
wrinkled, and rather rough. Colour yellow and dark brown. 
Length, 4 5 cm. ; breadth, 3 cm. 
Test thin, except at the posterior end where it is thickened, 
tough, and opaque ; white on section and on the inner surface. 
Mantle rather strong and muscular. 
Branchial sac with the folds very slight and distant, seven on 
each side. Internal longitudinal bars numerous, about nine on a 
fold and eight in the interspace, which has four wide and four narrow 
rows of meshes. Meshes containing each four stigmata, and often 
divided by a narrow horizontal membrane. 
Dorsal lamina formed of a series of narrow tentacular languets. 
Tentacles compound, very small, twelve larger ones with either one 
or two very minute ones between each pair of these. 
Olfactory tubercle very large but irregular ; broken up into a 
number of curved pieces. 
One specimen from Port Jackson, 2 to 10 fathoms. 
Cynthia pallida, Heller.* 
One specimen of this species from Simon’s Bay, 10 to 20 fathoms; 
two from Kandavu, Fiji ; and several small specimens from Papeete 
Harbour, Tahiti, 10 fathoms. 
* Beitrage zur nahern Kenntniss der Tunicaten, p. 14, Taf. iii. figs. 17, 18 
(Sitzb. d. k. Akad. d. Wiss., lxxvii. Bd., L Abth., 1878). 
