[alos 7 
XI. A further Contribution to the Knowledge of the existing Ziphioid Whales. Genus 
Mesoplodon. By Witiiam Henry Fiower, F.R.S., V.P.Z.S. 
Received July 31st, 1877. Read November 6th, 1877. 
{| PLates LX XI.-LXXIII.] 
DURING the six years that have elapsed since I communicated to the Society a 
memoir on the recent Ziphioid Whales (Trans. Zool. Soc. vol. viii. p. 203) very consi- 
derable additions have been made to our knowledge of the group. Instead of being 
so rare as was then supposed, since the attention of naturalists resident in our colonies 
has been directed to the importance of losing no opportunity of securing such specimens 
as accidents of wind and waves may cast upon their shores, it has been proved that in 
the seas of the southern hemisphere these Whales exist in considerable numbers both as 
species and as individuals, and that one species at least is gregarious, having been met 
with in two instances in “ schools” of considerable numbers. 
On the other hand, no remarkable deviations from the forms already known have 
been met with ; and all additional information as to their osteology has fully confirmed 
the value of the division of the Ziphioid Whales into four distinct types or genera, at 
that time indicated. With perhaps one exception (to be noticed further on), which 
presents some signs of transition, all the known individuals lately discovered can be 
arranged without any hesitation either as Hyperoodon, Berardius, Ziphius, or Meso- 
plodon, as defined in the previous memoir. 
It is in our knowledge of the animals of the last-named genus that the greatest 
advances have been made of late; and it is to these that the present communication 
will chiefly relate. 
After examining all the available specimens and published descriptions, I have 
arrived at the conclusion that evidence exists at present of six distinct specific modifica- 
tions of this form, of which four inhabit the southern temperate seas. To these I shall 
have to add two more, although in neither case on evidence so satisfactory as might be 
desired. The synonymy and habitats of the hitherto known species are as follows :— 
1. M. BrpEens (Sowerby). 
Physeter bidens, Sowerby, Brit. Miscellany, p. 1 (1804). 
Delphinus (Heterodon) sowerbiensis, Blainville, Nouv. Dict. d’Hist. Nat. 2nd ed. tome ix. p. 177 
(1817). 
D. sowerbyi, Desmarest, Mammalogie, p. 521 (1822). 
Delphinorhynchus micropterus, Cuvier, Régne Animal, t. i. p. 288 (1829) ; Dumortier, Mém. Acad. 
Roy. Bruxelles, t. xu. (1839). 
VoL, X.—ParT 1x. No. 2.—Augqust 1st, 1878. 3L 
