128 ON A FEMALE SPECIMEN OF THE COMMON RORQUAL
Beige, Avril, 1884, p. 365) mentions that the asymmetry noted by
Prof. Sars in B. musculus does not exist in B. borealis, and adds in a
note, "Cette couleur blanche, semi-laterale, que M. le Professeur
G. O. Sars a deja decrite, n'est pas exclusivement attachee a un cote
special, mais elle varie d'apres les observations que j'ai faites." I
am not aware of his having published any fuller information on this
interesting point.
In 1886, Prof. M. G. Pouchet of the Paris Museum, in a very
interesting memoir "De L'Asymetrie de la Face chez les Ceto-
dontes,"3 dealing chiefly with the osteological differences in toothed
whales, mentions the asymmetry of colour in B. musculus recorded
by Sars and Guldberg as a kind of pleuronectism, and adds :—
Si cette decoloration existe toujours du cote droit comme semble l'indiquer
Sars, elle constituerait pour les Balaenides une sorte de caractere abdominal, de
meme que la deviation de l'event des Cetodontes donne chez eux au cote gauche
une sorte de caractere dorsal. Un lien physiologique semblerait en ce cas relier
les deux particularites anatomiques, qui l'une et l'autre accuseraient une ten
dance au pleuronectisme du meme cote'."
In the Burnham specimen, not only is the asymmetry well
marked, but a curious deviation obtained. On the right side, as
may be seen in the illustration, a portion of the upper maxilla vary-
ing from 1 to 7 inches, about 2ft. of the baleen, and a curved margin
varying from 51/2 inches on the band of the lower jaw, being white,
whilst below this the throat is black, which colour extends in an
oblique line to the base of the pectoral flipper.
Why this species should exhibit such a remarkable feature, which
appears to be common also to both sexes ; and of what particular
use it can be to the animal is not known, nor does it seem possible
at present to advance any likely reason for the peculiarity.
In conclusion, I may mention that the flesh was used for
manurial purposes at Southminster, that the bones are now being pre-
pared by Mr. E. Gerrard, of Camden Town, for the owners, and the
skeleton will probably be articulated for exhibition at Burnham.
3 Prof. Pouchet very kindly sent me a copy of this rare Memoir, which he was deputed to
write and publish by the Nat. Hist. Mus. of Paris, in honour of the professorial jubilee of the
veteran cetologist, Van Beneden, Professor of the University of Louvain, whose works on the
osteology of living and fossil Cetacea, and other writings, are so well known to naturalists.