1908-9.] 
711 
The Skeleton of a Sowerby’s Whale. 
with M m and less so with Miy ; carpale 4 was probably fused with it. No 
os centrale was present, and the pisiform cartilage extended from ulna to 
5th metacarpal. 
The manus was pentadactylous. Digit I had its metacarpal 25 mm. 
long, somewhat conical and articulating by its proximal epiphysis with 
carpale l , whilst distally it was continuous with an unossified phalanx. The 
other metacarpals were flattened bones, which as well as the phalanges had 
proximal and distal epiphyses. The second metacarpal articulated with C 2 
and very slightly with C l ; its digit was the longest and had eight phalanges. 
The third articulated with carpalia 2 and 3 , and had six phalanges. The 
fourth, whilst 31 mm. in transverse diameter, was only 20 mm. long ; it articu- 
lated with carpale 3 and with the ulnare ; its two phalanges were short and 
flattened. The fifth metacarpal consisted of a bony nodule 24 mm. wide 
and 13 mm. long, which was imbedded in cartilage continuous with the 
pisiform, and there was no bony phalanx. 
A feature in this manus was the rudimentary condition of the fifth digit, 
the absence of carpale 5 , and no separate C 4 , though this element may have 
blended with the ulnare, or rather with carpale 3 (fig. 9), which articulated 
with both Mm and Miy. From the close relation of the fifth metacarpal 
with the ulnare, C 5 had either never been developed or had disappeared 
very early, either by atrophy, or by fusion with the ulnare or with My. So 
rudimentary was the fifth digit that in the manus of the younger of the two 
dolphins it was scarcely recognisable, and the manus almost seemed as if it 
were tetradactylous. 
The formula in the well-ossified manus of Risso’s dolphin was as 
follows : — 
Min. 
Ann. 
Med. 
Ind, 
Pollex. 
Ph 
Pli 2 
Ph 6 
i 
Pli 8 
Pip 
M v 
Miy 
1 
M m 
Mu 
Mi 
pis. 
cart. 
|k 
intermedium radiale 
Radius 
Delphinapterus leucas (Beluga or White Whale). 
In his memoir “ On the Hand in the Cetacea,” W. Kiikenthal described 
and figured the characters in an adult Beluga and in a number of embryos 
at various stages of development. The procarpus was typical. The 
mesocarpus was variable. In the youngest embryo five cartilaginous disto- 
carpalia C 2 to C 5 were recognisable. Carpale 5 however disappeared early, 
