ORCELLA. 255 
spiteful thud, and the cub, losing its balance, falls into the water, when _ 
in an instant it is seized by the remorseless whales.” The speed of the 
killer whale is immense, as may be supposed when it can overtake the 
swift dolphins, which it catches and swallows alive. It has also been 
seen chasing salmon up the mouths of rivers. 
The genus Orce/la seems to come in between the sea and river 
dolphins, although Orcella fluminalis of Dr. Anderson is a purely 
fluviatile animal, which apparently never goes out to sea. 
No. 258. ORCELLA BREVIROSTRIS. 
The Short-nosed Round-headed River Dolphin. 
Hasitat.—The estuaries of the Ganges and Brahmaputra rivers. 
Description.—“ The head is convex from the blow-hole to the 
upper lip, but its sides immediately below the angle of the mouth are 
somewhat anteriorly convergent, but rounded ; the gape posteriorly has 
a long upward curve; the eye, which is well developed, is near the 
angle at the gape, and in the adult is placed about one inch above it, 
with a slightly downward slope ; the ear is nearly on the same level as 
the angle of the mouth, but is extremely small, crescentic, and not 
measuring more than o'r2 inch in diameter. The posterior margin of 
the blow-hole is immediately behind the anterior angle of the eye; the 
blow-hole is crescentic and unsymmetrical, being more to the left than 
to the right side; there are two slight eminences about one inch behind 
the blow-hole ; the construction of the neck occurs below the ear and 
slightly behind it” (Anderson’s ‘ Anatomical and Zoological Researches,’ 
p: 370). The other characteristics are triangular flippers half as broad as 
long. The back fin rises behind the centre of the back ; it is compara- 
tively small, falcate, curved over the top to a blunt point, and concave 
behind. The line of the back is sharp from this fin down to the tail. 
The ventral line is the same for some inches behind the anus. The 
colour is dark slaty-blue above, almost black, a little paler below, without 
any streaks or marks, such as in O. flwminalis and Risso’s grampus. 
S1zE.—From snout to caudal notch, about 7 feet. 
I cannot find much on record concerning the habits of this dolphin, and 
my Own acquaintance with it is too limited for me to afford much original 
information. 
No. 259. ORCELLA FLUMINALIS (Avderson). 
The Fresh-water Round-headed Dolphin. 
Hasirat.—The Irrawaddy river ; Burmah. 
DeEscriptTion,—This differs from the last in a “ rather smaller, lower, 
and more falcate dorsal fin, its more pointed and less anteriorly bulging 
