202 DR. J. E. GRAY ON BRITISH CETACEA. [May 24, 
EuBALZENA AUSTRALIS. 
The tympanic bone is subcubical and rugose, the back is very 
much swollen, the inner edge is very protuberant, and forms an angle 
with the surface nearer the outer margin ; the upper portion is very 
prominent and subangular, and separated from the lower portion by 
two irregular depressions ; the hinder margin is very thick, convex, 
and rounded. ‘The lower surface is rather flattened, with an irre- 
gular-oblong, rather kidney-shaped aperture, which is very strongly 
plaited on the hinder margin, and nearly as long as the bone. 
Hab. Sea near the Cape of Good Hope. 
The periotic bones, with the tympanic bones 7m situ, are figured by 
Prof. Huxley in ‘Elem. Comp. Anat.’ fig. 109, from a specimen 
presented to the College of Surgeons by Dr. G. Bennett. 
We have three specimens similar to this figure in the British Mu- 
seum :—two, presented by H. H. Russell, Esq., as the ear-bone of 
the Sperm Whale; one from South Africa, presented by G. Byham, 
Esq., to the Paleeontological Department. 
Var.? In the British Museum there is a specimen of the periotic 
bones, with the tympanic bones attached, which we received with- 
out an habitat from Dr. Mantell. In several particulars it is very 
like the specimen of B. australis; but the hinder edge of the tym- 
panic bones, instead of being very thick and rounded, is much thinner 
than any part of the bone, and the periotic bones are much broader 
and more expanded. It may be only a variety of B. australis. I 
think it is better to give a short notice of it, for the sake of draw- 
ing the attention of future observers to the peculiarity. 
Var.? In the British Museum there is another imperfect worn 
tympanic bone, without any habitat, which resembles those of B. 
australis in general appearance ; but the hinder margin is shelved off 
and thin, instead of broad and rounded as in the typical specimens 
of that species. This may indicate an allied species, or only a va- 
riety. 
The Whalebone Whales may be thus characterized by their tym- 
panic bones :— 
* Tympanic bone rhombic ; aperture oblong, only slightly contracted 
at the upper end, and about two-thirds of the length of the 
bone. Batawna and EvBALANA. 
** Tympanic bone irregular rhombic; aperture irregular, much 
contracted at the upper end, and the wide part not half the 
length of the bone. CAPEREA. 
Bana (CAPEREA) ANTIPODARUM, Gray, Zool. E. & T. t.1. 9 
The tympanic bone oblong, rugulose ; the upper and outer margin 
thick and rounded; the lower edge truncated ; the back regularly 
convex, with a smooth, broad, slightly depressed portion just above 
the middle. 
